Дисертації: "Reduced Graphene Oxide-Silver Nanocomposite"

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Kim, K. B., J. G. Kim, H. K. Kim, J. P. Jegal, K. H. Kim, J. Y. Kim, and S. H. Park. "Nanocomposites of Reduced Graphene Oxide for Energy Storage Applications." Thesis, Sumy State University, 2012. http://essuir.sumdu.edu.ua/handle/123456789/35266.

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A well-crystallized and nano-sized Metal oxide/reduced graphene oxide composite material for lithium ion batteries has been successfully synthesized. The nano-sized metal oxide particles were evenly dispersed on the reduced graphene oxide template without any agglomeration, which allows the inherent high active surface area of individual metal oxide nano-particles in the composite. These unique structural and morphological properties of metal oxide on the highly conductive reduced graphene oxide sheets in the composite enable achieving the high specific capacity, and excellent high rate capability and stable cycling performance. an analysis of the cyclic voltammogram data revealed that a large surface charge storage contribution of the metal oxide/reduced graphene oxide nanocomposite plays an important role in achieving faster charge/discharge. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35266

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Sass, Danielle. "Nano silver-Iron-reduced graphene oxide modified titanium dioxide photocatalyst for the remediation of Organic dye in water systems." University of the Western Cape, 2018. http://hdl.handle.net/11394/6274.

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Magister Scientiae - MSc (Chemistry)
Drinking water with high concentrations of inorganic and organic contaminants can cause adverse health defects. Specifically methyl orange dye is an organic water contaminant that has been known (along with others like methyl blue etc.) to have an increase in our water systems over the past few years due to increasing demand in industrial processes. It is therefore of utmost importance to remediate organic contaminants and ultimately enable prevention. The contaminants can be removed by photocatalysis. Anatase TiO2 is known for its photocatalytic degradation of environmental pollutants and photoelectro-chemical conversion of solar energy. However its application is limited since it is a wide band gap semiconductor, (Eg = 3.2 eV). The following study deals with the enhancement of the photocatalytic properties of TiO2 for remediation of organic water contaminants. The study was carried out to produce the two nanocomposites AgFe-TiO2 and AgFe-TiO2-rGO photocatalyst which purpose is to be cheap and easy to apply, with improved (fast and effective) photocatalytic degradation of methyl orange. The main objective was to decrease the band gap and to introduce intra-band gap states to absorb visible light. Modification of the TiO2 with small bandgap semiconductor, graphene and Ag- Fe nanoalloy reduced the bandgap energy for visible light absorption and photocatalytic degradation of methyl orange dye. The two composites were synthesised using sonication and chemical synthesis methods. A photocatalytic study (degradation of methyl orange dye) was carried out using a system incorporating an UV lamp source to determine the degradation of methyl orange catalysed by the synthesised photocatalysts AgFe-TiO2-rGO and AgFe-TiO2 along with UV-vis Spectroscopy. Morphological studies were carried out using HRSEM and HRTEM which determined the spherical agglomerated nature of AgFe-TiO2 and the sheet-like nature of AgFe-TiO2-rGO containing spherical agglomerants but that also contained pockets formed by the sheets of the rGO. XRD served as confirmation of the phase of TiO2 in both composites to be anatase. Analysis confirmed the formation and elemental determination of both composites. It was observed that the Band gap of TiO2 degussa decreased from 2.94 eV to 2.77 eV in the composite AgFe-TiO2. The photocatalytic reactivity of AgFe- TiO2 was an improvement from TiO2 and AgFe-TiO2-rGO based on the photocatalytic study. Therefore concluding that AgFe-TiO2 was the best catalyst to convert the dye (Orange II) into free radicals and ultimately remove the contaminant from the water compared to AgFe-TiO2-rGO.

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Sass, Danielle Thandi. "Nano silver-iron-reduced graphene oxide modified titanium dioxide photocatalyst for the remediation of organic dye in water systems." University of the Western Cape, 2018. http://hdl.handle.net/11394/6410.

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Magister Scientiae - MSc (Chemistry)
Drinking water with high concentrations of inorganic and organic contaminants can cause adverse health defects. Specifically methyl orange dye is an organic water contaminant that has been known (along with others like methyl blue etc.) to have an increase in our water systems over the past few years due to increasing demand in industrial processes. It is therefore of utmost importance to remediate organic contaminants and ultimately enable prevention. The contaminants can be removed by photocatalysis. Anatase TiO2 is known for its photocatalytic degradation of environmental pollutants and photoelectro-chemical conversion of solar energy. However its application is limited since it is a wide band gap semiconductor, (Eg = 3.2 eV). The following study deals with the enhancement of the photocatalytic properties of TiO2 for remediation of organic water contaminants.
2021-12-31

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Yarmolenko, O. V., S. A. Baskakov, Y. M. Shulga, P. I. Vengrus, and O. N. Efimov. "Supercapacitors Based on Composite Polyaniline / Reduced Graphene Oxide with Network Nanocomposite Polymer Electrolyte." Thesis, Sumy State University, 2013. http://essuir.sumdu.edu.ua/handle/123456789/35510.

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The paper describes investigation on new types of supercapacitors based on composite polyani-line/reduced graphene oxide with network nanocomposite polymer electrolyte. Its prototypes are all solid state. The new network polymer electrolytes based on polyethylene glycol diacrylate and nanoparticle SiO2 was synthesized by reaction of radical polymerization in the environment of liquid organic electrolyte. The work is aimed to obtain a polymer electrolyte that is compatible with the electrode materials of superca-pacitors. For these purposes the method of FTIR spectroscopy, a.c. electrochemical impedance and gal-vanostatic cycling were used. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/35510

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Leve, Zandile Dennis. "Determination of paracetamol at the electrochemically reduced graphene oxide-metal nanocomposite modified pencil graphite (ERGO-MC-PGE) electrode using adsorptive stripping differential pulse voltammetry." University of Western Cape, 2020. http://hdl.handle.net/11394/7350.

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>Magister Scientiae - MSc
This project focuses on the development of simple, highly sensitive, accurate, and low cost electrochemical sensors based on the modification of pencil graphite electrodes by the electrochemical reduction of graphene oxide-metal salts as nanocomposites (ERGO-MC-PGE; MC = Sb or Au nanocomposite). The electrochemical sensors ERGO-Sb-PGE and ERGO-Au-PGE were used in the determination of paracetamol (PC) in pharmaceutical formulations using adsorptive stripping differential pulse voltammetry. The GO was prepared from graphite via a modified Hummers’ method and characterized by FTIR and Raman spectroscopy to confirm the presence of oxygen functional groups in the conjugated carbon-based structure whilst, changes in crystalline structure was observed after XRD analysis of graphite and GO.
2023-10-07

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Aher, Ashish. "SYNTHESIS, CHARACTERIZATION AND APPLICATIONS OF REDUCED GRAPHENE OXIDE AND COMPOSITE MEMBRANES FOR SELECTIVE SEPARATIONS AND REMOVAL OF ORGANIC CONTAMINANTS." UKnowledge, 2019. https://uknowledge.uky.edu/cme_etds/111.

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Among the next generation materials being investigated for membrane development, partially reduced Graphene Oxide (rGO) has received increasing attention from the membrane community. rGO-based nanofiltration membranes have shown promising results in applications such as partial desalination, organic contaminant removal, gas-phase separations, and separations from solvent media. rGO offers a unique platform compared to common polymeric membranes since it can be used for separation applications in both aqueous and organic solvent media. An rGO-based platform could also be utilized to synthesize reactive membranes, giving rGO membranes the additional capability of reactively removing organic contaminants. This research focuses on the synthesis of rGO and nanocomposite membranes for applications including the separation of high-value phenolic compounds from a solvent-water mixture, removal of organic contaminants, and treatment of refinery wastewater. First, the behavior of a rGO membrane in water and isopropanol was investigated along with its ability to separate high-value, lignin-derived oligomeric compounds from a solvent-water mixture. This study revealed the formation of stable sorbates of water in the GO channels that resulted in declined membrane permeance and improved size-exclusion cutoff. Through controlled reduction of GO by heat treatment, it was demonstrated that physicochemical properties of the GO membrane could be modulated and separation performance tuned based on the extent of reduction. A varying degree of interlayer spacing was attained between the GO laminates by controlling the O/C ratio of GO. This allowed the rGO membrane to achieve tunable molecular separation of lignin-derived model oligomeric compounds from a solvent-water mixture. Second, the mechanism of ionic transport through the rGO membrane was studied as well as its application in partial desalination and removal of persistent organic contaminants from water. Through comprehensive experimental investigations and mathematical analysis, along with the aid of the extended Nernst Planck equation, the impacts of steric hindrance and charge interactions on the underlying ion transport mechanism were quantified. Charge interactions were observed to be the dominant exclusion mechanism for the rGO membranes. The application of rGO membranes for treatment of high TDS produced water was investigated with the goal of partial hardness and dissolved oil removal. In addition, this study demonstrated the removal of emerging organic contaminants, specifically perfluorooctanoic acid, by rGO membranes and elucidated a charge interaction-dominated exclusion mechanism for this contaminant, as well. Finally, rGO-based and microporous polyvinylidene fluoride (PVDF)-based catalytic membrane platforms were synthesized for removal of organic contaminants via an oxidative pathway. Herein, an advanced oxidation process was integrated with membrane technology by the in-situ synthesis of Fe-based nanoparticles. The unique capability to oxidatively remove contaminants in a continuous mode of operation was explored in addition to the separation performance of the membrane. The rGO-based platform achieved high oxidative removal of trichloroethylene via a sulfate-free, radical-mediated pathway, while simultaneously removing humic acids from water and potentially eliminating undesired side reactions. A PVDF-based microporous catalytic membrane platform was shown to effectively remove organic impurities, such as Naphthenic acids, from high TDS produced water by the same pathway. The enhancement of reaction extent for elevated temperatures and longer residence times was also quantified in this study. These studies benefit the membrane community in the following ways: 1) The work identifies the critical role of the physicochemical properties of GO, such as the O/C ratio and water sorption, for determining the permeability-selectivity of rGO membranes for solvent nanofiltration. 2) Investigations of ion transport through rGO membranes led to an understanding of a charge-dominated separation mechanism for ion retention. The Nernst-Planck equation-based approach employed in this study would enable further assessment and comparison of rGO membranes under a wide set of parameters. 3) Catalytic membrane platforms (rGO and microporous PVDF-based) were synthesized for conducting advanced oxidation reactions in the porous membrane domain, demonstrating potential applications in environmental remediation of organic contaminants.

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Al-Nafiey, Amer Khudair Hussien. "Reduced graphene oxide-based nanocomposites : synthesis, characterization and applications." Thesis, Lille 1, 2016. http://www.theses.fr/2016LIL10009/document.

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Nous avons synthétisé avec succès ces nano-composés (rGO/Arg-Ag NPs, rGO-Ni NPs and rGO-Co3O4NPs) et les avons caractérisés par de nombreuses techniques, XPS, SEM, TEM, FTIR, Raman, UV-Vis et TGA. Les analyses montrent que ces nano-composés à base de graphène ont des propriétés excellentes et une grande stabilité. Utilisés comme catalyseurs dans des applications environnementales, ils réduisent efficacement le 4-nitrophenol en 4-aminophenol ainsi que les colorants à forte adsorption et le chrome (VI) présents dans les eaux usées
We successfully obtained these nanocomposites (rGO/Arg-Ag NPs, rGO-Ni NPs and rGO-Co3O4NPs).The resulting rGO-based nanocomposites were characterized by a variety of different techniques, including XPS, SEM, TEM, FTIR, Raman, UV-Vis and TGA. These analysis shows that these graphene-based nanocomposites have excellent properties and stability. The rGO-based nanocomposites, applied as a catalyst in environmental applications and shows good catalytic performance for reduction of 4nitrophenol to 4aminophenol and high adsorption dyes and Cr (VI) from wastewater

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Ammar, Ali M. "REDUCTION OF GRAPHENE OXIDE USING MICROWAVE AND ITS EFFECT ON POLYMER NANOCOMPOSITES PROPERTIES." University of Akron / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=akron1533123263694685.

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Bai, Xiaoyun. "Development of reduced graphene oxide based nanocomposities for electrochemical biosensing applications." HKBU Institutional Repository, 2014. https://repository.hkbu.edu.hk/etd_oa/228.

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The modification of electrodes is always an important task in electrochemical detection of electroactive and biological molecules. Chemically modified electrodes can offer improved selectivity and sensitivity for the target analyte, which greatly enhance the electrode performance. Various materials such as conducting polymers, metal nanoparticles and carbon nanomaterials have been exploited and widely used for the modification of electrodes. Electrochemical or spontaneous deposition, electrostatic adsorption, layer-by-layer self assembly and covalent binding have also been developed for electrode modification and offer improved performance. Both Prussian blue (PB) and toluidine blue O (TBO) are excellent redox mediators and very popular in electrode modification. PB has shown strong catalytic property for the reduction of hydrogen peroxide, but the application in biosensor fabrication is limited for its instability at neutral pH. Graphene, as a single-atom-thick carbon material, is considered an ideal platform for designing composite nanomaterials for high-performance electrochemical or electrocatalytic devices. The combination of PB with reduced graphene oxide (RGO) and poly(toluidine blue O) (PTBO) will greatly improve the stability of PB. An amperometric biosensor based on glassy carbon (GC) electrode modified with reduced graphene oxide, PB and poly(toluidine blue O) was developed. Experimental results showed that the GC/RGO/PB/PTBO modified electrode offered an excellent electrocatalytic activity toward the reduction of hydrogen peroxide due to the possible synergistic effects of the PB-PTBO composite material. After codeposition of glucose oxidase (GOD) and chitosan (CHIT) coating, the resulting GC/RGO/PB/ PTBO/CHIT-GOD electrode exhibited excellent response to glucose with a sensitivity of 59 mA M1 cm2, a low detection limit of 8.4 μM and a linear range from 0.02 to 1.09 mM at a detection potential of +0.2 V vs. Ag.

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Ly, Kally Chein Sheng 1992. "Fabricação e caracterização de filme fino regenerável hidrofóbico." [s.n.], 2017. http://repositorio.unicamp.br/jspui/handle/REPOSIP/330349.

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Orientador: Antonio Riul Júnior
Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Física Gleb Wataghin
Made available in DSpace on 2018-09-02T14:50:41Z (GMT). No. of bitstreams: 1 Ly_KallyCheinSheng_M.pdf: 2442128 bytes, checksum: 86716c6c19fa3a9db425b32c36463141 (MD5) Previous issue date: 2017
Resumo: Materiais biomiméticos são inspirados em estruturas biológicas para a obtenção de propriedades e funcionalidades específicas. Dentre os materiais biomiméticos, os que são capazes de se regenerar (self-healing) despertaram grande interesse pelo potencial de aplicação em diversas áreas. Para ilustrar, alguns materiais autorregeneráveis poliméricos apresentam regeneração múltipla, necessitando apenas de água para que a regeneração ocorra em alguns minutos, aumentando consideravelmente a proteção mecânica da superfície contra desgastes, danos mecânicos entre outros. Entretanto, múltiplas imersões em água ou em meios aquosos pode degradar o material e neste contexto este projeto visa incorporar a hidrofobicidade a um sistema regenerável. Desta forma, o material regenerável hidrofóbico, durante sua regeneração imersa em água, poderá diminuir a interação da superfície não danificada com a água, reduzindo corrosões e degradações devido a meios aquosos. Estudamos a nanoestruturação de materiais através da técnica de automontagem por adsorção física (LbL, do inglês Layer-by-Layer) utilizando os polieletrólitos poli(etileno imina) (PEI) e poli(ácido acrílico) (PAA), a fim de produzir revestimentos capazes de se regenerar a danos mecânicos micrométricos. Adicionalmente, foram incorporados a estes dois materiais nanofolhas de óxido de grafeno reduzido (rGO) funcionalizados com poli(cloridrato de alilamina) (GPAH) e poli(estireno-sulfonato de sódio) (GPSS), com o intuito de verificarmos um aumento de resistência a abrasão do material e alterações nas propriedades elétricas na nanoestrutura formada para aumentar o potencial de aplicação em eletrônica flexível. A arquitetura molecular (GPAH-PEI/GPSS-PAA)60 foi caracterizada com espectroscopia Raman, medidas de ângulo de contato, microscopia de força atômica, medidas elétricas e nanoindentação. Foi observada boa regeneração do material após 15 minutos de imersão em água a temperatura ambiente em um dano mecânico da ordem de 10 micrômetros. Também observamos boa hidrofobicidade do filme LbL (GPAH-PEI/GPSS-PAA)60 ( teta = 136º), e medidas de microscopia de força atômica e perfilometria indicaram, respectivamente, rugosidade superficial de 55 nm em uma área de (2 ?m x 2 ?m) e espessura de filme de 30 ?m. A análise Raman apontou para uma forte interação das nanofolhas de rGO com os polímeros, corroborando o tem caráter elétrico isolante do filme (GPAH-PEI/GPSS-PAA)60, que apresentou função trabalho ~ 5,2 eV e condutividade elétrica da ordem de 10-7 S/cm, que acreditamos resultar das fortes interações das nanofolhas com os polímeros. Por fim, medidas de nanoindentação indicaram que a incorporação de nanofolhas de GPSS e GPAH aumentou em 10 vezes a dureza do nanocompósito formado, sem comprometer a regeneração
Abstract: Biomimetic materials are inspired in biological structures to obtain specific properties and functionalities and among them, those capable of self-healing brought great interest due to high potential of application in different areas. To illustrate, some polymeric self-healing materials present multiple regeneration in the presence of water, with the regeneration occurring within a few minutes, increasing considerably the mechanical protection of a surface against wear and mechanical damage among others. Nevertheless, multiple immersions in water or in aqueous media can degrade the material and in this context this project aims the incorporation of hydrophobicity to a self-healing system. In this way, the self-healing, hydrophobic material during its immersion in water may decrease the interaction of the damaged surface with water, reducing corrosion and degradation due to aqueous media. We study the nanostructuration f materials through the layer-by-layer (LbL) technique using poly(ethylene imine) (PEI) and poly(acrylic acid) (PAA) in order to produce self-healing coatings from micrometric mechanical damages. In addition, we also incorporate to these materials reduced graphene oxide (rGO) functionalized with poly(allylamine hydrochloride) (GPAH) and poly(styrene-sodium sulfonate) (GPSS), with the purpose of verifying an increase in the mechanical abrasion resistance of the material and changes in the electrical properties of the nanostructures formed to increase the potential application in flexible electronics. The molecular architecture (GPAH-PEI/GPSS-PAA)60 was characterized by Raman spectroscopy, contact angle measurements, atomic force microscopy, electrical measurements and nanoindentation. It was observed good self-healing capacity after 15 min f immersion in water at room temperature in a mechanical scratch of the order of 10 micrometers. It was also observed good hydrophobicity in the (GPAH-PEI/GPSS-PAA)60 LbL film ( teta = 136º) and atomic force microscopy and perfilometer indicate, respectively, surface roughness of 55 nm in a (2 ?m x 2 ?m) area and film thickness of 30 ?m. Raman analysis pointed out to a strong physical interaction between the rGO nanoplatelets with the polymeric materials, corroborating the strong insulating nature of (GPAH-PEI/GPSS-PAA)60 film that displayed a work function of 5.2 eV and electrical conductivity of 10-7 S/cm, which we believe results from the strong interactions of the nanosheets with the polymers. Finally, nanoindentation measurements indicated that the incorporation of GPAH and GPSS nanoplatelets increased hardness by 10 times, without compromising the regeneration
Mestrado
Física
Mestra em Física
1543078/2015
CAPES

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Salimian, Maryam. "Advances in multifunctional nickel/reduced graphene oxide nanocomposites, synthesis and characterization." Doctoral thesis, Universidade de Aveiro, 2018. http://hdl.handle.net/10773/23709.

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Doutoramento em Engenharia Mecânica
O grafeno é constituído por uma monocamada de átomos de carbono dispostos numa espécie de rede hexagonal perfeita. Devido às suas propriedades extraordinárias, este nanomaterial tem suscitado um grande interesse tanto no setor científico como no industrial. A este respeito, a investigação em torno do grafeno mostrou um aumento exponencial em áreas tão diferentes como a energia, biomedicina, eletrónica, entre outras. O óxido de grafeno (GO), um dos derivados de grafeno, foi considerado como um substrato interessante para o desenvolvimento de nanocompositos. Isto deve-se fundamentalmente à presença de grupos funcionais de oxigénio na superfície do grafeno, os quais proporcionam locais reativos para a nucleação e o crescimento de outras estruturas. O níquel (Ni) é um metal de transição muito abundante na terra, possui uma superfície brilhante comum à maioria dos metais e é dúctil e maleável possuindo propriedades magnéticas e catalíticas superiores, condutividade térmica e elétrica razoáveis sendo muito utilizado em diferentes aplicações. As nanopartículas (NPs) de Ni são utilizadas como catalisadores heterogéneos e receberam atenção notável devido ao seu baixo custo, reduzida toxicidade, baixa corrosão, entre outras características. Desta forma, a funcionalização do GO com NPs de Ni pode constituir uma nova família de nanocompósitos com propriedades sinérgicas. Esta tese está focada no controlo da síntese de nanocompósitos Ni/GO, uma vez que o tamanho, a morfologia e a dispersão de NPs de Ni no grafeno afetam as suas funcionalidades e estão em dependência direta com as metodologias de síntese. Em primeiro lugar, foi usado um método hidrotérmico de fácil implementação e execução num passo único. Foram estudados vários parâmetros de síntese, incluindo temperatura, tempo de reação e agente redutor. O controlo destes parâmetros influenciou efetivamente o tamanho das NPs de Ni, variando estas de 150 a 900 nm, a morfologia variou de forma esférica a formato em espiga e de partículas finas bem distribuídas para agregados. Em seguida, o controlo do tamanho das NPs de Ni para valores inferiores a 10 nm e com distribuição de tamanho reduzido no substrato foi conseguido através de um procedimento de síntese em dois passos com base num método solvotérmico seguido por tratamento térmico sob atmosfera redutora de H2. O tempo de reação mostrou ser um fator chave para controlar a distribuição e o tamanho das NPs de Ni simultaneamente com a redução do GO (rGO). O aquecimento em atmosfera de H2 foi crucial para formar as NPs de Ni metálicas cristalinas. A influência de um tratamento térmico adicional em atmosferas redutora e inerte sobre a estrutura do nanocompósito Ni/rGO foi também investigada. Diferentes nanocompósitos apresentaram boa estabilidade térmica sob H2 até à temperatura de 450 °C durante 2 horas. O tratamento a 900 °C sob o fluxo de árgon alterou a estrutura do Ni/rGO por formação de “sulcos” através da rede de carbono e coalescência das NPs de Ni com formação de partículas maiores. O estudo das propriedades eletrofisicas dos nanocompositos Ni/rGO mostrou que estas são dependentes do tamanho e estrutura das NPs de Ni nas folhas de rGO. Esta é uma potencial vantagem do método de síntese desenvolvido para o design de diferentes nanocompositos de Ni/rGO que poderão ser materiais favoráveis para aplicação em dispositivos eletrónicos integrados.
Graphene, the world thinnest material made of carbon atoms in a dense honeycomb network has captured a great interest in both scientific and industry sectors due to its remarkable properties. In this regard, the graphene research is facing an incredible rise in different areas such as energy, biomedical, sensor and electronic applications, between others. Graphene oxide (GO), one of the graphene derivatives, has been considered as an interesting substrate to build nanocomposites. This is due to the presence of oxygen functionalities at the graphene surface which provides reactive sites for the nucleation and growth of other structures. Nickel (Ni) is a transition metal very abundant on earth, it has a shiny surface common to most metals and is both ductile and malleable possessing different properties such as superior magnetic and catalysis properties, a fairly good heat and electrical conductivity and is widely used in different areas of application. Ni nanoparticles (NPs) find use as heterogeneous catalyst and received noteworthy attention because of its inexpensive, non-toxic, low corrosion, waste minimization, between other characteristics. In this way, the functionalization of GO with Ni NPs can establish a new family of nanocomposites with synergic properties. This thesis is focused on the control of the synthesis of Ni/GO nanocomposites, since the size, morphology and dispersion of Ni NPs on graphene affect their functionalities and are in direct dependence with the synthesis methodologies. First, a facile one pot hydrothermal method was introduced and various synthesis parameters including temperature, reaction time and reducing agent were investigated. The control of these parameters effectively influenced the Ni size, ranging from 150 to 900 nm, the morphology from spherical to spiky shape and from well distributed fine particles to the big aggregation. Then, the control of the Ni NPs size to values of less than 10 nm with narrow size distribution on the substrate was achieved via a two-step synthesis procedure based on a solvothermal method followed by a heat treatment under H2 reducing atmosphere. The reaction time was shown to be a key factor to control the size and size distribution of Ni NPs simultaneously through the reduction of GO (rGO). Heating treatment under H2 was crucial to form the crystalized metallic Ni NPs. The influence of further thermal treatment under reducing and inert atmospheres on the structure of Ni/rGO nanocomposite was also investigated. Different nanocomposites showed a good thermal stability under H2 up to 450°C during 2 hours’ treatment. Higher temperature (900°C) under Argon flow changed the structure of Ni/rGO by formation of trenches through the carbon etching and coalescence of Ni NPs to form bigger particles. The study of the electrophysical properties of Ni/rGO showed that these properties are dependent on the size and structure of Ni NPs on rGO nanosheets. This is the potential advantage of the synthesis method developed for designing different matrix of Ni/rGO nanocomposites which could be a favorable material for integrated electronic devices application.

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Chunder, Anindarupa. "FABRICATION OF FUNCTIONAL NANOSTRUCTURES USING POLYELECTROLYTE NANOCOMPOSITES AND REDUCED GRAPHENE OXIDE ASSEMBLIES." Doctoral diss., University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/3082.

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A wide variety of nanomaterials ranging from polymer assemblies to organic and inorganic nanostructures (particles, wires, rods etc) have been actively pursued in recent years for various applications. The synthesis route of these nanomaterials had been driven through two fundamental approaches - Â Top downÂ and Â Bottom upÂ . The key aspect of their application remained in the ability to make the nanomaterials suitable for targeted location by manipulating their structure and functionalizing with active target groups. Functional nanomaterials like polyelectrolyte based multilayered thin films, nanofibres and graphene based composite materials are highlighted in the current research. Multilayer thin films were fabricated by conventional dip coating and newly developed spray coating techniques. Spray coating technique has an advantage of being applied for large scale production as compared to the dip coating technique. Conformal hydrophobic/hydrophilic and superhydrophobic/hydrophilic thermal switchable surfaces were fabricated with multilayer films of poly(allylaminehydrochloride) (PAH) and silica nanoparticles by the dip coating technique, followed by the functionalization with thermosensitive polymer-poly(N-isopropylacrylamide)(PNIPAAM) and perfluorosilane. The thermally switchable superhydrophobic/ hydrophilic polymer patch was integrated in a microfluidic channel to act as a stop valve. At 70 degree centigrade, the valve was superhydrophobic and stopped the water flow (close status) while at room temperature, the patch became hydrophilic, and allowed the flow (open status). Spray-coated multilayered film of poly(allylaminehydrochloride) (PAH) and silica nanoparticles was fabricated on polycarbonate substrate as an anti-reflection (AR) coating. The adhesion between the substrate and the coating was enhanced by treating the polycarbonate surface with aminopropyltrimethoxylsilane (APTS) and sol-gel. The coating was finally made abrasion-resistant with a further sol-gel treatment on top of AR coating, which formed a hard thin scratch-resistant film on the coating. The resultant AR coating could reduce the reflection from 5 to 0.3% on plastic. Besides multilayered films, the fabrication of polyelectrolyte based electrospun nanofibers was also explored. Ultrathin nanofibers comprising 2-weak polyelectrolytes, poly(acrylic acid) (PAA) and poly(allylaminehydrochloride) (PAH) were fabricated using the electrospinning technique and methylene blue (MB) was used as a model drug to evaluate the potential application of the fibers for drug delivery. The release of MB was controlled in a nonbuffered medium by changing the pH of the solution. Temperature controlled release of MB was obtained by depositing temperature sensitive PAA/poly(N-isopropylacrylamide) (PNIPAAM) multilayers onto the fiber surfaces. The sustained release of MB in a phosphate buffered saline (PBS) solution was achieved by constructing perfluorosilane networks on the fiber surfaces as capping layers. The fiber was also loaded with a real life anti-depressant drug (2,3-tertbutyl-4-methoxyphenol) and fiber surface was made superhydrophobic. The drug loaded superhydrophobic nanofiber mat was immersed under water, phosphate buffer saline and surfactant solutions in three separated experiments. The rate of release of durg was monitored from the fiber surface as a result of wetting with different solutions. Time dependent wetting of the superhydrophobic surface and consequently the release of drug was studied with different concentrations of surfactant solutions. The results provided important information about the underwater superhydrophobicity and retention time of drug in the nanofibers. The nanostructured polymers like nanowires, nanoribbons and nanorods had several other applications too, based on their structure. Different self-assembled structures of semiconducting polymers showed improved properties based on their architectures. Poly(3-hexylthiophene) (P3HT) supramolecular structures were fabricated on P3HT-dispersed reduced graphene oxide (RGO) nanosheets. P3HT was used to disperse RGO in hot anisole/N, N-dimethylformamide solvents, and the polymer formed nanowires on RGO surfaces through a RGO induced crystallization process. The Raman spectroscopy confirmed the interaction between P3HT and RGO, which allowed the manipulation of the composite's electrical properties. Such a bottom-up approach provided interesting information about graphene-based composites and inspired to study the interaction between RGO and the molecular semiconductor-tetrasulphonate salt of copper phthalocyanine (TSCuPc) for nanometer-scale electronics. The reduction of graphene oxide in presence of TSCuPc produced a highly stabilized aqueous composite ink with monodispersed graphene sheets. To demonstrate the potential application of the donor (TSCuPc)Â acceptor (graphene) composite, the RGO/TSCuPc suspension was successfully incorporated in a thin film device and the optoelectronic property was measured. The conductivity (dark current) of the composite film decreased compared to that of pure graphene due to the donor molecule incorporation, but the photoconductivity and photoresponsivity increased to an appreciable extent. The property of the composite film overall improved with thermal annealing and optimum loading of TSCuPc molecules.
Ph.D.
Department of Chemistry
Sciences
Chemistry PhD

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13

Karna, Sanjay K. "Enhancement of Light Emission from Metal Nanoparticles Embedded Graphene Oxide." Thesis, University of North Texas, 2005. https://digital.library.unt.edu/ark:/67531/metadc849637/.

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A fully oxidized state of graphene behaves as a pure insulating while a pristine graphene behaves as a pure conducting. The in-between oxide state in graphene which is the controlled state of oxide behaves as a semiconducting. This is the key condition for tuning optical band gap for the better light emitting property. The controlling method of oxide in graphene structure is known as reduction which is the mixed state of sp2 and sp3 hybrid state in graphene structure. sp2 hybridized domains correspond to pure carbon-carbon bond i.e. pristine graphene while sp3 hybridized domains correspond to the oxide bond with carbon i.e. defect in graphene structure. This is the uniqueness of the graphene-base material. Graphene is a gapless material i.e. having no bandgap energy and this property prevents it from switching device applications and also from the optoelectronic devices applications. The main challenge for this material is to tune as a semiconducting which can open the optical characteristics and emit light of desired color. There may be several possibilities for the modification of graphene-base material that can tune a band gap. One way is to find semiconducting property by doping the defects into pristine graphene structure. Other way is oxides functional groups in graphene structure behaves as defects. The physical properties of graphene depend on the amount of oxides present in graphene structure. So if there are more oxides in graphene structure then this material behaves as a insulating. By any means if it can be reduced then oxides amount to achieve specific proportion of sp2 and sp3 that can emit light of desired color. Further, after achieving light emission from graphene base material, there is more possibility for the study of non-linear optical property. In this work, plasmonic effect in graphene oxide has been focused. Mainly there are two kinds of plasmon effects have been studied, one is long range (surface) and short range (localized) plasmon. For long range plasmon gold thin film was deposited on partially reduced graphene oxide and for short range plasmon silver nanoparticles have used. Results show that there are 10-fold enhancement in light emission from partial graphene oxide coated with gold thin film while 4-fold enhancement from reduced graphene oxide solution with silver nanoparticles. Chemical method and photocatalytic method have been employed for the reduction of graphene oxide for the study of surface plasmon and localized plasmon. For the characterization UV-Vis spectrometer for absorption, spectrofluorophotometer for fluorescent emission, Raman spectrometer for material characterization, photoluminescence and time resolved photoluminescence have been utilized. Silver and gold nanoparticles are spherical of average size of 80 nm and 40 nm have been used as plasmons.

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14

Karna, Sanjay K. "Enhancement of Light Emission from Metal Nanoparticles Embedded Graphene Oxide." Thesis, University of North Texas, 2016. https://digital.library.unt.edu/ark:/67531/metadc849637/.

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Анотація:

A fully oxidized state of graphene behaves as a pure insulating while a pristine graphene behaves as a pure conducting. The in-between oxide state in graphene which is the controlled state of oxide behaves as a semiconducting. This is the key condition for tuning optical band gap for the better light emitting property. The controlling method of oxide in graphene structure is known as reduction which is the mixed state of sp2 and sp3 hybrid state in graphene structure. sp2 hybridized domains correspond to pure carbon-carbon bond i.e. pristine graphene while sp3 hybridized domains correspond to the oxide bond with carbon i.e. defect in graphene structure. This is the uniqueness of the graphene-base material. Graphene is a gapless material i.e. having no bandgap energy and this property prevents it from switching device applications and also from the optoelectronic devices applications. The main challenge for this material is to tune as a semiconducting which can open the optical characteristics and emit light of desired color. There may be several possibilities for the modification of graphene-base material that can tune a band gap. One way is to find semiconducting property by doping the defects into pristine graphene structure. Other way is oxides functional groups in graphene structure behaves as defects. The physical properties of graphene depend on the amount of oxides present in graphene structure. So if there are more oxides in graphene structure then this material behaves as a insulating. By any means if it can be reduced then oxides amount to achieve specific proportion of sp2 and sp3 that can emit light of desired color. Further, after achieving light emission from graphene base material, there is more possibility for the study of non-linear optical property. In this work, plasmonic effect in graphene oxide has been focused. Mainly there are two kinds of plasmon effects have been studied, one is long range (surface) and short range (localized) plasmon. For long range plasmon gold thin film was deposited on partially reduced graphene oxide and for short range plasmon silver nanoparticles have used. Results show that there are 10-fold enhancement in light emission from partial graphene oxide coated with gold thin film while 4-fold enhancement from reduced graphene oxide solution with silver nanoparticles. Chemical method and photocatalytic method have been employed for the reduction of graphene oxide for the study of surface plasmon and localized plasmon. For the characterization UV-Vis spectrometer for absorption, spectrofluorophotometer for fluorescent emission, Raman spectrometer for material characterization, photoluminescence and time resolved photoluminescence have been utilized. Silver and gold nanoparticles are spherical of average size of 80 nm and 40 nm have been used as plasmons.

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15

Dywili, Nomxolisi Ruth. "Development of Metal Nanoparticle-Doped Polyanilino-Graphene Oxide High Performance Supercapacitor Cells." University of the Western Cape, 2018. http://hdl.handle.net/11394/6251.

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Philosophiae Doctor - PhD (Chemistry)
Supercapacitors, also known as ultracapacitors or electrochemical capacitors, are considered one of the most important subjects concerning electricity or energy storage which has proven to be problematic for South Africa. In this work, graphene oxide (GO) was supported with platinum, silver and copper nanoparticles anchored with dodecylbenzenesulphonic acid (DBSA) doped polyaniline (PANI) to form nanocomposites. Their properties were investigated with different characterization techniques. The high resolution transmission electron microscopy (HRTEM) revealed GO's nanosheets to be light, flat, transparent and appeared to be larger than 1.5 ?m in thickness. This was also confirmed by high resolution scanning electron microscopy (HRSEM) with smooth surfaces and wrinkled edges observed with the energy dispersive X-ray analysis (EDX) confirming the presence of the functional groups such as carbon and oxygen. The HRTEM analysis of decorated GO with platinum, silver and copper nanoparticles (NPs) revealed small and uniformly dispersed NPs on the surface of GO with mean particle sizes of 2.3 ± 0.2 nm, 2.6 ± 0.3 nm and 3.5 ± 0.5 nm respectively and the surface of GO showed increasing roughness as observed in HRSEM micrographs. The X-ray fluorescence microscopy (XRF) and EDX confirmed the presence of the nanoparticles on the surface of GO as platinum, silver and copper which appeared in abundance in each spectra. Anchoring the GO with DBSA doped PANI revealed that single GO sheets were embedded into the polymer latex, which caused the DBSA-PANI particles to become adsorbed on their surfaces. This process then appeared as dark regions in the HRTEM images. Morphological studies by HRSEM also supported that single GO sheets were embedded into the polymer latex as composite formation appeared aggregated and as bounded particles with smooth and toothed edges.

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16

Santos, Pãmyla Layene dos 1990. "Obtenção fotoquímica de nanocompósito baseado em azul da Prússia e óxido de grafeno reduzido." [s.n.], 2015. http://repositorio.unicamp.br/jspui/handle/REPOSIP/250675.

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Анотація:

Orientador: Juliano Alves Bonacin
Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química
Made available in DSpace on 2018-08-27T15:22:06Z (GMT). No. of bitstreams: 1 Santos_PamylaLayenedos_M.pdf: 4212017 bytes, checksum: 32d8be4cbad15f721c18e5490e98cb35 (MD5) Previous issue date: 2015
Resumo: O azul da Prússia (AP) é um dos mais antigos compostos de coordenação e pode ser utilizado na modificação de sensores eletroquímicos para a detecção de H2O2, o AP pode catalisar a redução do peróxido e por isso é conhecido como "artificial peroxidase". Entretanto, filmes de AP não apresentam boa estabilidade eletroquímica e alternativas como a obtenção de nanocompósito baseados em AP e grafeno podem ser utilizadas para contornar o problema. O grafeno é um material com alta condutividade, flexibilidade e resistência à tração, pode ser obtido pelo método de Hummers que consiste na redução do óxido de grafeno e neste caso é chamado de óxido de grafeno reduzido. Assim, o objetivo deste trabalho é a obtenção fotoquímica de um nanocompósito baseado em azul da Prússia (AP) e óxido de grafeno reduzido (rGO) que permite uma combinação das propriedades eletrocatalíticas do AP e condutoras do rGO para a aplicação em sensores eletroquímicos. Além disso, espera-se uma maior estabilidade eletroquímica deste material. Os materiais óxido de grafeno reduzido e azul da Prússia foram obtidos separadamente pelos métodos químicos e fotoquímicos com a utilização de LEDs. Os resultados mostraram vantagens do método fotoquímico como o controle da morfologia e do tamanho dos cristais de azul da Prússia. O grau de redução dos materiais baseados em grafeno foi controlado com o tempo de irradiação no LED e isso foi refletido em suas propriedades eletroquímicas, com uma resposta linear da corrente de pico em função do grau de redução. O nanocompósito foi obtido pelo método fotoquímico in situ, e isso foi comprovado pelas técnicas DRX, espectroscopias Raman e UV-Vis. As micrografias obtidas por FEG-SEM mostraram a presença de cubos de AP sobre toda a superfície do óxido de grafeno reduzido. Espera-se que a interação entre o AP e rGO permita uma maior estabilidade eletroquímica do material que será testado no sensoriamento de H2O2
Abstract: Prussian blue is one of the oldest coordination compounds and can be used on the modification of electrochemical sensors for the detection of H2O2, PB can catalyze the reduction of hydrogen peroxide and, for that, it is known as "artificial peroxidase". However, PB films do not show good electrochemical stability and alternatives such as the obtention of nanocomposites based on PB and graphene can be used to work around this problem. Graphene is a material with high conductivity, flexibility and tensile strength. Graphene can be obtained by Hummers method, which consists of reducing graphene oxide, in which case it is called a reduced graphene oxide. The goal of this work is photochemically obtaining a nanocomposite based on Prussian blue (PB) and reduced graphene oxide (rGO) that allows a combination of the electrocatalytical properties of PB and high conductivity of rGO for use in electrochemical sensors. In addition, we expect a higher electrochemical stability of this material. Reduced graphene oxide and Prussian blue were obtained separately by chemical and photochemical methods using LED. The results show the advantages of photochemical method to control the morphology and size of Prussian blue crystals. The reduction extent of graphene-based material was controlled by the irradiation time of the LED and this was reflected in its electrochemical properties, with a linear response of the peak current depending on the reduction extent. The nanocomposite was obtained by in situ photochemical method, and this was confirmed by XRD techniques, Raman and UV-Vis. The micrographs obtained by FEG-SEM showed the presence of PB cubes on the entire surface of the reduced graphene oxide. It is expected that the interaction between the PB and rGO allowing greater electrochemical stability of the material to be tested in H2O2 sensing
Mestrado
Quimica Inorganica
Mestra em Química

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17

Ya-ChiKo and 柯雅淇. "Preparation and application of Ag/ZnO/reduced graphene oxide nanocomposite." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/03458305987687493846.

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Анотація:

碩士
國立成功大學
化學工程學系
103
In this study, Ag/ZnO/reduced graphene oxide (Ag/ZnO/rGO) nanocomposite was fabricated and its applications in the detection and killing of bacteria were investigated. This nanocomposite combined the photocatalytic property of ZnO nanoparticles, the high specific surface area and near infrared (NIR) photothermal conversion property of rGO, and the bacteria-killing capability and surface enhanced Raman scattering (SERS) property of Ag nanoparticles. At first, ZnO/rGO nanocomposite was prepared from zinc acetate and graphene oxide (GO) by solvothermal method in the mixture of ethylene glycol and NaOH aqueous solution. The influences of GO content on the growth of ZnO nanoparticles on the surface of rGO and the photocatalytic property were examined to obtain a ZnO/rGO nanocomposite with better photocatalytic activity. Secondly, in the silver nitrate-containing arginine solution, Ag nanoparticles were deposited on the surface of ZnO/rGO nanocomposite by microwave-assisted method. It was demonstrated that the resulting Ag/ZnO/rGO nanocomposite not only could be successfully used as the SERS substrate for the detection of E-Coli, but also could be used for the efficient killing of E-Coli in the dark and under the full Xe lamp or NIR irradiation via the Ag nanoparticles-related and photocatalytic or photothermal killing mechanisms. The full Xe lamp irradiation led to the best bacteria-killing efficiency and the second best one was observed under NIR irradiation. This revealed that the Ag/ZnO/rGO nanocomposite could provide more ways and better performance for killing bacteria as compared to the individual Ag nanoparticles. Accordingly, the Ag/ZnO/rGO nanocomposite developed in this study indeed possessed both the bacteria detection and killing properties.

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18

Wang, Hsiao-Wen, and 王曉雯. "Polyaniline/Reduced Graphene Oxide/Carbon Nanotube Ternary Nanocomposite as Supercapacitor Electrode." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/x77pvx.

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Анотація:

碩士
國立雲林科技大學
化學工程與材料工程系
104
The aim of this study is to investigate the effect of preparation procedures on the Polyaniline (PANI)/Reduced Graphene Oxide (RGO)/Carbon Nanotube (c-CNT) Ternary Nanocomposite as Supercapacitor Electrode. The processes respectively are : (1)Two step synthesis method：First, reduced GO into RGO and mixed with c-CNT. Then in-situ polymerization of PANI on the surface of RGO/c-CNT.：(2)Three step synthesis method A：First, in-situ polymerization of PANI on the surface of GO/c-CNT then reduction/de-doping and re-doping. Process (1) and (2) are study the mixing method of polymerization effect of electrode material. The mixing methods are mechanical stirring (MS) and ultrasonic irradiation (UI). The oxidant of aniline (ANI) is ammonium persulfate (APS)；re-dopant is HCl；The reducing agent of GO is NaBH4. The mixing method used MS can control shape of polyaniline. From Cyclic voltammetry test, the products used process (1) and (2) have better capacitance value. Then study the process (3) Three step synthesis method B：First, in-situ polymerization of PANI on the surface of GO that used MS then reduction/de-doping and re-doping to obtain PA7RGO3-S. At last add the c-CNT. Use the zeta potential analyzer to analysis the zeta potential of PA7RGO3-S and c-CNT that in aqueous solution of different pH value (pH=1, 3, 5). PA7RGO3-S and c-CNT are in aqueous solution with pH=5 there are large surface potential difference. Compare of different processes, the Three step synthesis method B have better capacitance value with PA7RGO3-S and c-CNT are 95:5wt%. By the cyclic voltammetry, three different processes of polyaniline/reduced graphene oxide of the electrochemically active area and specific capacitance values are significantly different, order (3) Three step synthesis method B > (2) Three step synthesis method A >Process(1) Two step synthesis method. Final, used composition is (PANI/RGO/c-CNT=85:14.85:0.15 wt %) from literature [15] to prepare PANI/RGO/c-CNT. Then compare of capacitance value that Three step synthesis method B have better capacitance value and cycle test (104%) than literature [15].

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19

Wang, Jing-Huei, and 王景暉. "Polyaniline-Reduced Graphene Oxide-Copper nanoparticles Nanocomposite for Ammonia Gas Sensing." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/5q8s47.

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Анотація:

碩士
義守大學
化學工程學系暨生物技術與化學工程研究所
105
In this study, we aimed to develop a highly sensitive and selective room temperature ammonia sensors, and it was achieved by using a polyamine-reduced graphene oxide nanocomposite sensing layer. The sensing material comprised polyaniline and reduced graphene oxide because polyamine could sense ammonia at room temperature and reduced graphene oxide exhibited good electric properties. Compared with different materials, the response of composites at room temperature is was higher then polyaniline ammonia sensor . The ammonia sensing linear range form 200 ppm to 250 ppb. . Temperature effect and flow rate effects were also studied. Long-term stability of the nanocomposite ammonia sensor was evaluated. The experimental results suggested that this nanocomposite sensor exbilted high sensitivity, selectiviety, and stability for ammonia sensing at room temperature.

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20

Neella, Nagarjuna. "Development of Graphene Metal Nanocomposite Resistive Films for Flexible Sensors and Body Warmer Applications." Thesis, 2018. http://etd.iisc.ac.in/handle/2005/4263.

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Mankind’s desire is to replicate the nature’s creation provided an impetus and inspiration to the rapid advancements, especially progress made in the sensors and other devices for next generation technologies from nanoscience and engineering. Generally, human being has five basic sensory organs, which helps to perform routine tasks in normal life. This clearly signify the importance of basic sensory organs in a human life. In a similar way, sensors and other devices are very important for most of the scientific and engineering applications. The aim of the present thesis work is to explore the application possibilities of graphene and its derivative based films deposited on a flexible substrate for the development of sensors and other devices. Different types of flexible/rigid substrates such as Kapton, Cotton Cloth and Stainless Steel were chosen for different applications. Drop casting and Dip coating techniques were adopted for the deposition of graphene and its derivative based films onto the above-mentioned substrates. The necessary process parameters were optimized to achieve good quality films. To explore the applications in sensors and other devices have been developed by utilizing the direct transformation of graphene and its derivative nanomaterial-based films deposited on flexible/rigid substrates by above mentioned techniques. These devices include temperature sensor for measurement of environmental parameters, heating element devices on cotton cloth for wearable body warmer (in clod places). On the other hand, using piezoresistive effect of graphene and its derivative nanomaterial film strain gauges for force sensor have also been developed. This includes, a film nanomaterial of graphene and its derivatives was used for tensile test of force sensor/device, which work as a load cell. The present thesis work is divided into the following six chapters.

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21

Kuok, Fei-Hong, and 郭飛鴻. "Reduced graphene oxide/carbon nanotube nanocomposite supercapacitor fabricated using atmospheric pressure plasma jet." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/79qdxg.

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Анотація:

碩士
國立臺灣大學
應用力學研究所
105
This study investigates the reduced graphene oxides (rGOs), carbon nanotubes (CNTs), and CNT/rGO composites sintered by nitrogen dc-pulse atmospheric-pressure plasma jet (APPJ). The sintered nanoporous materials are used for the electrodes of supercapacitors. The rGO/CNTs was coated on the electrode by screen printing and sintered by APPJ. Optical emission spectroscopy results indicate that the vigorous interaction between the nitrogen APPJ and the carbon. The nitrogen doping effect on carbon fiber cloth was observed by EPMA and XPS. The optimum process time for rGO and CNTs is 15 to 30 s. APPJ sintering significantly improves the charge storage and capacitance value. Evaluated by cyclic voltammetry under a potential scan rate of 2 mV/s, the best achieved specific capacitances are 82.5, 67.3, and 60.6 F/g for 15-s APPJ-sintered pure rGO, 15-s APPJ-sintered rGO/CNT and 30-s APPJ-sintered pure CNT supercapacitors, respectively. The specific capacitance is 145.3 F/g (areal capacitance = 10.6 mF/cm2) with a H2SO4/polyvinyl alcohol (PVA) gel electrolyte pure rGO supercapacitors.

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22

GAO, WAN-YING, and 高婉楹. "Polypyrrole/Reduced Graphene Oxide Nanocomposite as Supercapacitor Electrode-Effects of Morphology Control and Preparation Procedure." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/24707793484930774861.

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Анотація:

碩士
國立雲林科技大學
化學工程與材料工程系
104
The aim of this study is to investigate the different morphology control and preparation procedure for the preparation of polypyrrole (PPy)/reduced graphene oxide (RGO) nanocomposite electrode materials applied on the impact of supercapacitor electrode. By means of various synthesis parameters (the oxidant, the dopant, pathways) and other fixed parameters (reaction time, temperature, auxiliary doping acid concentration, etc.) prepared of PPy and PPy/GO of three different morphology, namely, nanowires, nanoclips, and nanospheres. The morphology can be observed by SEM images. Further reduced the GO to RGO, prepared PPy / RGO nanocomposite. By the cyclic voltammetry, three different morphology of polypyrrole (PPy) of the electrochemically active area and specific capacitance values are significantly different, order nanowires (PPy-W)> nanoclips (PPy-C)> nanospheres (PPy-S). Followed by the same parameters, GO and pyrrole monomer with a composite weight ratio of 7: 3 was synthesized by three kinds of different morphology material named PPy7GO3, and compare the electrochemically active area and specific capacitance values are significantly different, order nanowires(PPy7GO3-W)> nanoclips (PPy7GO3-C)> nanospheres (PPy7GO3-S). Because of poor conductivity of graphene oxide, RGO active surface area significantly higher than the GO. After prepared PPy7GO3, We are further chemical reduction method will reduce the GO into RGO, and re-doping, the synthesis method is called three-step synthesis method. Cyclic voltammetry showed that the electrochemically active area and specific capacitance values not as expected to enhance the effect of specific capacitance, but dropped significantly. Due to two-step synthesis method instead of three-step synthesis method, two-step synthesis method reduced the GO to RGO and then synthesis with Py monomer to PPy7RGO3. By the cyclic voltammetry, two-step synthesis method compared with three-step synthesis method has a higher specific capacitance values. Then, this study synthesized PPy7RGO3 nanocomposite by a novel one-step synthesis method. The one-step synthesis method used hydroiodic acid and Acetic acid not only as a oxidant but as a dopant, simultaneously GO reduced and polymerization with pyrrole monomers in an acidic environment. Comparison of three kinds of preparation procedure by the cyclic voltammetry, the electrochemically active area and specific capacitance values are significantly different, order PPy7RGO3 (HI, 1-step) > PPy7RGO3 (HI, 2-step) > PPy7RGO3 (SB, 3-step). Its showed PPy7RGO3 (HI, 1-step) has better specific capacitance values, PPy7RGO3 (HI, 1-step) have a higher specific capacitance values (543 F/g) than others at 5 mV/s scan rate. In order to compared with most of the studies in the literature, increased the ratio of GO and pyrrole monomer with a composite to 95:5 was synthesized material named PPy95RGO5(HI, 1-step). It’s specific capacitance up to 748 F/g at 5 mV/s scan rate. Followed by electrochemical impedance spectroscopy (EIS), showed PPy95RGO5(HI, 1-step) has the lowest charge transfer impedance, so that its electrochemical properties of composite materials are preferred. From the above study, through control morphology and the preparation of procedures, to the best performance of PPy / RGO nanocomposite as supercapacitor electrode.

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23

WU, YI-LIN, and 吳一霖. "Polypyrrole/Reduced Graphene Oxide Nanocomposite as Supercapacitor Electrode-Effects of Preparation Procedures and Doping Effect." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/7cd8qn.

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Анотація:

碩士
國立雲林科技大學
化學工程與材料工程系
106
The ain of this study is to investigate the effects of dopants and different preparation procedures for the preparation of polypyrrole(PPy)/reduced graphene oxide(RGO) nanocomposite electrode materials applied on the impact of supercapacitor electrode. Firstly, different groups of PPy are prepared by different (dopant types), and PPy-Dopant with better performance is selected, and then PPy-Dopant with different concentration ratios is synthesizes by different (oxidant concentration, dopant concentration). The best electrochemical performance of PPy-Dopant was selected. Finally, two groups of different dopants and different material concentration ratios of PPy were synthesized, which were PPy-DBSA and PPy-CTAB. During the experiment, it was found that the chemical in-situ polymerization of PPy and PPy/GO composite materials, the order of addition of dopants and pyrrole monomers, had a significant effect on the integrity after polymerization, by cyclic voltammetry ( CV) shows that the electrochemical active areas of PPy (CTAB), PPy (DBSA) and PPy (CTAB) 7GO3, PPy (DBSA) 7GO3 in two different processes are significantly different, and the electrochemical area is compared with each other. The order of adding the pyrrole after the dopant is greater than the order of adding the pyrrole and then adding the dopant. Because GO has poor conductivity and the electrochemical active area of RGO is larger than GO, PPy/GO is further prepared into PPy/RGO. There are three ways to process respectively: two-step synthesis (polymerization of PPy/GO, then reduction to PPy/RGO), two-step synthesis(reduction of RGO, then polymerization to PPy/RGO), one-step synthesis (simultaneous polymerization and PPy(DBSA)7RGO3 prepared by the preparation methods showd that the electrochemical activity area of PPy(DBSA)7RGO3 was larger than that of PPy(CTAB)7RGO3 prepared by three processes. The result proves that DBSA is The best dopant is used to prepare PPy7RGO3. It is known that DBSA is the best dopant for the preparation of PPy7RGO3, and PPy(DBSA)7RGO3 prepared by one-step synthesis (simultaneous polymerization and reduction) has the highest specific capacitance value 574 F/g at a scan rate of 5 mV/s, and PPy(DBSA)7RGO3 prepared by two-step synthesis (first polymerization) has the second highest specific capacitance value 538 F/g. Because of the different process methods, the electrochemical active area is also different, so two processes of PPy (DBSA) 7RGO3 were tested for a series of electrochemical activities. The results show that PPy(DBSA)7RGO3 prepared by two-step synthesis (first polymerization) has an optimum retention rate of 73% and a long charge and discharge time at 0.5 A/g constant current charge and discharge, and a one-step synthesis method. PPy(DBSA)7RGO3 prepared by simultaneous polymerization and reduction has the largest electrochemical active area and specific capacitance value under cyclic voltammetry (CV) of 5 mV/s.

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24

Wen-ChiChang and 張文吉. "Fabrication of NaYF4:Yb, Er/ reduced graphene oxide nanocomposite with NIR upconversion fluorescence imaging and photothermal therapy." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/19333196351256241552.

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Анотація:

碩士
國立成功大學
化學工程學系碩博士班
101
In this thesis, graphite oxide was synthesized by modified Hummers method and then reduced and surface modified with L-arginine via the microwave method to yield the well-dispersed reduced graphene oxide at first. Secondly, the NaYF4:Yb, Er nanoparticles with near infrared (NIR) upconversion fluorescence imaging property were synthesized, surface coated with silica nanoshells, and then further modified with 3-(triethoxysilyl)propylsuccinic anhydride to generate carboxylic groups on the surface of silica nanoshells. Finally, they were covalently bound on the arginine-modified reduced graphene oxide to form the nanocomposite combining the functions of NIR upconversion fluorescence imaging and photothermal therapy. By transmission electron microscopy (TEM), atomic force microscope (AFM), X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), Raman spectra, electron spectroscopy for chemical analysis (ESCA), UV/VIS/NIR spectrophometer, and fluorescence spectrophotometer, the products’ morphologies, sizes, crystalline structures, and optical properties were characterized. It was found that the formation of reduced graphene oxide, NaYF4:Yb,Er nanoparticles, and their nanocomposite has been achieved successfully. In addition, by using a HeLa cancer cell line, it was demonstrated this nanocomposite indeed possessed both the functions of NIR photothermal therapy and fluorescence imaging.

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25

Chang, Che Wei, and 張哲維. "A hybrid nanocomposite of molybdenum disulfide and reduced graphene oxide as counter electrode for dye-sensitized solar cells." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/4a64yt.

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Анотація:

碩士
國立清華大學
工程與系統科學系
103
In this study, the molybdenum disulfide/ nitrogen doped graphene oxide nanocomposite (MoS2/nGO) was synthesized with nitrogen doped reduced graphene oxide (nGO) by hydrothermal synthesis method and molybdenum disulfide (MoS2) by thermal reduce method. This hybrid nanocomposite coated on fluorine doped tin oxide (FTO) glass as a platinum-free counter electrode (CE). The characteristics of MoS2/nGO were investigated by high-resolution transmission electron microscopy (HRTEM) and Raman spectroscopy. The electrochemical property of MoS2/nGO was characterized by cyclic voltammetry (CV), electrochemical impedance spectra (EIS) and Tafel-polarization measurement. This MoS2/nGO CE exhibited well photovoltaic conversion efficiency (PCE = 5.95 %). Compared with the conventional Platinum, the MoS2/nGO CE was up to 93.4% of using conventional Pt CE (PCE = 6.43 %). As a result of the MoS2/nGO nanocomposite could provide an alternative selection to replace the noble platinum as CE for DSSCs.

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26

MonsaludEbuen, Anna Sophia, and 游安純. "Study of Piezo-related and Photoelectrochemical Properties of Pristine Bi4Ti3O12 and Bi4Ti3O12-Reduced Graphene Oxide Nanocomposite Thin Films." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/w9az4m.

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Анотація:

碩士
國立成功大學
材料科學及工程學系
106
Bi4Ti3O12 films and Bi4Ti3O12/rGO composites on FTO substrates were fabricated using a facile sol-gel method and were investigated regarding its piezo-related capabilities, photocatalysis, and PEC properties. UV-illumination and a hydrothermal approach were employed to reduce GO to rGO, which was ascertained through XRD, Raman and XPS. The bonding between Bi4Ti3O12 and rGO was also ascertained through XPS because of the presence of the Ti-O-C peak on the samples of Bi4Ti3O12/rGO (UV) and Bi4Ti3O12/rGO (hydro). The piezo-related studies of the pristine Bi4Ti3O12, Bi4Ti3O12/rGO (UV), and Bi4Ti3O12/rGO (hydro) indicated minor piezotronic and piezophototronic effects, which was attributed to poor inducement of piezopotential because of random distribution of Bi4Ti3O12 crystals instead of well aligned morphology. However, the photocatalytic and piezophotocatalytic properties of the samples were promising, wherein Bi4Ti3O12/rGO (hydro) sample exhibited the best performance with k of approximately 24  10-3/min-1, which was 4~5 times higher than that of the pristine Bi4Ti3O12. In addition, the excellent photoelectrochemical performance of composite samples was preliminarily determined from the observation of an enhancement in its photocurrent density under visible light illumination. The photocatalytic properties were consistent with the deduced energy band diagram, which showed that a more negative conduction band positions than the formation potential of superoxide radicals (O2/•O2-) was ideal for photodegradation applications, and that the conduction and valence band edge potentials straddled the hydrogen and oxygen redox potentials was excellent for overall photoelectrochemical water splitting.

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27

LIN, CHUN-CHIA, and 林俊嘉. "Study on Antibacterial Efficiency Using NRC-03 Peptide Conjugated Dopamine-Modified Reduced Graphene Oxide Nanocomposite Under Near-Infrared Illumination." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/fmsgkg.

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28

Peng, Shih-Liang, and 彭士樑. "WO3 / reduced graphene oxide nanocomposite films were fabricated by combining one-pot polyol process with metal organic decomposition method for NO2 sensing at room-temperature." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/s98t2w.

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Анотація:

碩士
中國文化大學
化學系應用化學碩士班
103
One-pot polyol process was combined with metal organic decomposition (MOD) method to fabricate a room-temperature NO2 gas sensor based on tungsten oxide and reduced graphene oxide (WO3/RGO) nanocomposite films. X-ray diffractometry (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to analyze the structure and morphology of the fabricated films. Comparative gas sensing results indicated that the sensor that was based on the WO3/RGO nanocomposite film had much more response than that based on pure WO3 film in detecting NO2 gas at room temperature. Microstructural observations revealed that RGO was embedded in the WO3 matrix. Therefore, a model of potential barriers to electronic conduction in the composite material was used to reveal that the high response was associated with the stretching of the two depletion layers at the surface of the WO3 film and at the interface between the WO3 film and the RGO when detected gases are adsorbed at room temperature. The sensor that was based on a nanocomposite film of WO3/RGO responded strongly to low concentrations of NO2 gas at room temperature and its use is practical because of it is easy to fabricate.

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29

Tzu-YangLin and 林子揚. "Preparation and application of iron oxide/ reduced graphene oxide nanocomposites." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/jzz2ce.

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Анотація:

碩士
國立成功大學
化學工程學系
102
This thesis concerns the preparation of iron oxide/reduced grapheme oxide nanocomposites and their applications in adsorption and supercapacitor. For the first part, an arginine-capped nanocomposite of iron oxide nanoparticles and reduced graphene oxide (iron oxide/rGO) has been synthesized as a magnetic nano-adsorbent for the removal of acid dyes AO12 and AG25 via a facile one-step green route with L-arginine as the reducing agent and capping agent. It was quite efficient for the adsorption of acid dyes due to the electrostatic interaction and the van der Waals force or π−π interaction between the acid dyes and the arginine-capped iron oxide/rGO nanocomposite. Moreover, the adsorption for both acid dyes obeyed the Langmuir isotherms. In addition, the adsorption process obeyed the pseudo second-order kinetic model. Also, both acid dyes could be desorbed by NaOH solution and the iron oxide/rGO nanocomposite exhibited good reusability. For the second part, rGO and iron oxide nanoparticles were deposited on the surface of nickel foam (NF) successively via a two-step hydrothermal method to obtain a 3-D iron oxide/rGO/NF composite electrode for supercapacitors. In addition to examine the effect of reaction time for the deposition of rGO on the followed iron oxide deposition and the capacitance, it was also shown that the capacitance of composite electrode was much higher than those of iron oxide/NF and rGO/NF and even their sum. This revealed the iron oxide and rGO of composite electrode exhibited a significant synergistic effect.

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30

Ke, Ming-Qing, and 柯明青. "Effect of thermally reduced graphene oxide on the Properties of Supercritical CO2 Foamed Polystyrene/Graphite Nanocomposites." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/434kaf.

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Анотація:

碩士
國立臺北科技大學
化學工程研究所
100
Polymeric foam possesses many advantages such as cost reduction, insulation, weight saving, high modulus/density ratio and improved fatigue resistance. It has been commonly used in livelihood tools, aerospace and the automotive industry. In addition, the graphene research increased dramatically in recent years. It has great electrical properties, mechanical properties, thermal properties, high specific surface area. Due to the availability and easiness of production, the price of graphene could be lower than that of carbon nanotubes and carbon nano fibers in the future. One of the characteristics of graphene is its ultrahigh specific surface area which would improve the nucleation rate during the foaming process. Thus, graphene was compounded with polystyrene and polymer-graphene nanocomposite foam was prepared using a batch foaming technique. Combining the advantages of polymer nanocomposite and foam may create a new class of lightweight, high strength materials which could have many new possibilities. In the first part of this study, natural graphite was oxidized by Hummers method and followed by thermal reduction to obtain graphene nanoplatelets. The graphene and graphite oxide nanoparticles were characterized by XRD, EDS and FTIR .In the second part of this study, graphene was compounded with polystyrene by solvent blending. The dispersion of grapheme was characterized by TEM. Finally, the polymer-graphene nanocomposites were foamed using supercritical carbon dioxide as the blowing agent using a batch foam process. The graphene/polystyrene nanocomposites were foamed at 120 ° C and various foaming pressure. The foam structure was characterized by SEM. The experiment results showed that adding nanoparticles can significantly enhance the nucleation rate and decrease the cell size. To compare the nucleation effect of different nanoparticles, thermally reduced graphene (TRG), carbon nanotubes, carbon nano fiber, commercially available nanographite platelets and talc were used as nucleating agents. Among the different nanoparticles, graphene showed the best nucleating efficiency. The cell size is 7.8 μm while the cell density is 3.54×109cell/cm3foamed at 120˚C and 2000 psi. In addition, it is worth noting that adding nanoparticles as a nucleating agent can make foams of similar cell size and cell density with a much lower foaming pressure.

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31

Lin, Jia-Hui, and 林嘉暉. "Synthesis and characterization of Iron Oxide (IO)/FePt/ reduced graphene oxide (rGO) nanocomposites." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/5a8nw9.

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Анотація:

碩士
國立臺北科技大學
製造科技研究所
104
In this study, FePt/reduced graphene oxide (rGO) nanocomposies have been synthesized using a chemical reduction. Triethylene glycol (TEG) as both solvent and reductant, whereas graphene oxide (GO) nanosheets as a supported of FePt nanoparticles. And the precursor of Iron Oxide (IO) have been added at different times in to the synthesis of FePt/rGO nanocomposite to prepared the different structures of Iron Oxide/FePt/rGO nanocomposites. The microstructure, composition, surface morphology and magnetic property of this nanocomposites are methodically characterized by XRD, FI-IR, Raman spectrum, SEM, VSM, high-frequency heater, potentiostat and 808nm infrared diode laser. The above analysis result, it can be observed that the different peaks of rGO, IO and FePt in the XRD pattern. Raman spectroscopy can be observed the peaks of IO between 200 to 800 cm-1 and checking the phase of IO, and the main feature G and D band of rGO that between 1000 to 2000 cm-1. From the FT-IR spectrum, Fe-O, -OH, C-H, C-O and C=C were observed respectively. The saturation magnetization (Ms) of IO/FePt/rGO nanocomposites have been increased through the addition of iron oxide. Observing the properties of the sample through high-frequency heater. In the electrochemical analysis result that adding iron oxide could reduce the CO poisoning effect. Finally, the sample at the wavelength of 808 nm infrared laser have excellent property of photothermal therapy.

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32

LAI, CHI-HUAI, and 賴祈淮. "Preparation of silver/thiol reduced graphene oxide composites for conductive materials." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/g8rs57.

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Анотація:

碩士
國立臺北科技大學
資源工程研究所
107
In recent years, due to the rapid development of the electronics industry, the characteristics of a single material can not meet the progress of the times. In this study, the surface properties and electrical properties of reduced graphene oxide were mainly used to adsorb silver ions after modification with MPTMS, thereby improving the conductivity of reduced graphene oxide. The study is divided into four parts: The first part is the discussion on the modification of graphene oxide. The solvothermal method is used to prepare thiol-graphene oxide. The mechanism of MPTMS on the degree of surface modification and surface reaction of graphene oxide is discussed. The second part is to investigate the effect of thiol-graphene oxide on the adsorption of Ag(I) in silver nitrate at different pH, time, concentration and temperature, and discuss its adsorption mode. The third part is to use L-ascorbic acid as a reducing agent to investigate the change between surface thiol-graphene oxide and silver metal particles before and after silver/thiol-graphene oxide reduction. The fourth part is to discuss the conductivity analysis of silver/thiol-reduced graphene oxide and silver/reduced graphene oxide. The experimental results show that L-ascorbic acid can effectively reduce graphene oxide without destroying the mercaptan structure in MPTMS. In this study, the optimal mass of MPTMS was 5%, and after the adsorption, the surface silver ions were reduced to silver metal particles. After the reduction, the amount of extra silver added could reach 4469 S/cm, so the silver/thiol reduction oxidation was used in this study. Graphene has the potential of conductive materials.

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33

Shih-TingWang and 王詩婷. "Photoluminescence of solvothermal reduced graphene oxide with surface decoration by silver nanoparticles." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/66318123361425299704.

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Анотація:

碩士
國立成功大學
材料科學及工程學系碩博士班
101
N-methly-2-pyrrolidone (NMP) has been used for efficient extraction of coals due to its high-boiling point and oxygen-scavenging properties. In this study, we performed reduction of graphene oxide (GO) with NMP/H2O open-air system and demonstrated fast and efficient reduction within two hours. In the first part of this work, we synthesized graphene oxide with modified Hummer’s method as starting material, and characterized its structure and chemical properties. In the second part, we provided a hydrothermal-solvothermal transition at about 60-80 minutes of reduction that causes efficient removal of oxygen-containing functional groups, and rapid decrease of band gap from about 3 eV to 1 eV during the reduction process. Moreover, a 30-40 eV blue shift in the green emission region was shown in photoluminescence (PL) characterization, which correlates to the structural restoration of sp2 carbon rings. In the last part of work, NMP was used in developing silver nanoparticles-decorated (reduced) GO sheets, which exhibited enhancement in the PL intensity by surface plasmon resonance and size adjustable properties of silver nanoparticles. In summary, tunable optical properties by reducing GO with a fast and efficient solvothermal method is provided in this work. In addition, the use of NMP as chemical reagent improves stabilization of silver nanoparticles on reduced GO with adjustable size, and enhancement of the emission intensity. We expect this work to attribute in the development in optoelectronics, energy, and biomedical techniques.

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34

Chun-ChiehYeh and 葉俊杰. "Preparation and catalytic properties of Ni-based nanoparticles/reduced graphene oxide nanocomposites." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/ykbu5a.

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Анотація:

碩士
國立成功大學
化學工程學系
102
This thesis concerns the fabrication and catalytic application of nickel/reduced graphene oxide (Ni/rGO) and nickel sulfide/reduced graphene oxide (NiS/rGO). Ni/rGO has been developed as a magnetic recoverable catalyst with near-infrared (NIR) photothermally enhanced activity owing to the magnetic and catalytic properties of Ni nanoparticles as well as the large specific surface area and excellent NIR photothermal conversion property of rGO. By the hydrazine reduction in ethylene glycol, Ni ions and graphene oxide were reduced simultaneously to form the Ni/rGO. The resulting Ni/rGO with about 62 wt% of Ni nanoparticles was nearly superparamagnetic and possessed good catalytic activity toward the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) with sodium borohydride. The corresponding pseudo-first-order rate constants increased with increasing the temperature and 4-NP concentration, revealing the synergistic effect of rGO. Furthermore, under NIR irradiation, it was demonstrated that the Ni/rGO could efficiently enhance the reduction rate via the photothermal conversion. In addition, by the reaction with sodium sulfide, Ni/rGO could be successfully transferred to NiS/rGO as a good visible-light photocatalyst for the degradation of methylene blue. The corresponding pseudo-first-order rate constant was significantly higher than those using NiS, rGO, and S/rGO as the photocatalysts. This might be due to the good electron transfer property and synergistic effect of rGO, and demonstrated that NiS/rGO indeed had good photocatalytic activity for the degradation of methylene blues.

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35

Li, Dong Lin, and 李東霖. "Fabrication of Zerovalent Iron/Reduced Graphene Oxide Nanocomposites for Dechlorination of Trichloroethene." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/15701969961873086125.

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Анотація:

碩士
國立清華大學
生醫工程與環境科學系
104
Nanoscale zerovalent iron (nZVI) has been widely used in environmental remediation. It has low toxicity, abundance in the world, suitable potential for triggering the reduction make it a promising material in decades. However, the ferromagnetism of ZVI nanoparticles leads to aggregation, causing low reactivity and mobility. In recent years, using solid supports for nZVI is one of the methods enhancing its reactivity. In this study, a facile approach for the synthesis and immobilization of ZVI nanoparticles onto reduced graphene oxide (rGO) have developing by adding NaBH4 as reducing agent. By adjusting the weight ratio between iron precursors and graphene oxide, we can purchase the well-dispersed ZVI nanoparticles on reduced graphene oxide. In this study, the diameter of particles of rGO-Fe nanocomposites was about 44.1 nm. Its pseudo-first rate constant (kobs) of TCE degradation can reach to 9.40×10-3 h-1, which was 3 times higher than conventional ZVI. Due to synergetic effect, adding second metal ions can significantly enhanced the reactivity of rGO-Fe nanocomposites. The kobs for TCE degradation were 5.89, and 53.6 h-1 at 1.877 mM Ni(II), 0.105 mM Pd(II). Both of them are much higher than rGO-Fe nanocomposites alone ( 9.40×10-3 h-1). The result obtained in this study proving that immobilization of ZVI nanoparticles on reduced graphene oxide is successful in water treatment. Its high reactivity and large surface area make it have potential developing in multifunctional use in environmental application.

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36

Chen, Ying-Hui, and 陳盈慧. "Reduced graphene oxide and nano silver and copper composite film in biosensor applications." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/pvm6ad.

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Анотація:

碩士
國立臺北科技大學
化學工程研究所
102
Part 1 ：The present work describes the characterization of a chemically reduced graphene oxide (CRGO) modified glassy carbon electrode (GCE) for electrochemical investigation of caffeic acid (CA). Cyclic voltammetry (CV), differential pulse voltammetry (DPV), amperometry, and electrochemical impedance spectroscopy (EIS) techniques were used to characterize the properties of the electrode. There was an obvious enhancement of the current response and a decreased over potential for the oxidation of CA. The interfacial electron transfer rate of CA was studied by EIS. Under optimal conditions, the CRGO displayed a linear response range of 1×10-8 to 8×10-4 M and the detection limit was 2×10-9 M (S/N = 3), with a sensitivity of 192.21 μA mM-1 cm-2 at an applied potential of +0.2 V (vs. Ag/AgCl reference), which suggests that the CRGO is a promising sensing materials for the electrochemical investigation of CA. The results showed the good sensitivity, selectivity and high reproducibility of the CRGO modified electrode. Moreover, this modified electrode was further applied to investigate the CA in real samples of wine with satisfactory results. Part 2 ：Rapid synthesis of silver nanoparticles through economically feasible green chemistry approach is highly desirable. In this study we have developed a method to biosynthesize silver nanoparticles by mixing silver solution with leaf extract of Chenopodium ambrosioides L. In this method, physiologically stable, bio-compatible Ag nanoparticles (AgNPs) were formed. These nanoparticles were analyzed by various characterization techniques to reveal their morphology, chemical composition, and bioactivity. Average crystal size calculated from SEM, FE-SEM and AFM respectively. The particle size ranging from 100 to 300 nm and the shape of the plate and spherical structures could be controlled by changing the reaction temperature and leaf broth concentration. The concentrations of leaves extract and metal ion are playing an important role in the green synthesis of AgNPs. The spectroscopic characterizations from XRD and Cyclic voltammetry (CVs) support the formation and stability of the biosynthesized AgNPs. This simple, efficient and rapid green synthesis of AgNPs can be used in various biomedical and biotechnological applications. This environmentally friendly method of biological AgNPs synthesis can potentially be applied in various products that directly come in contact with the human body, such as cosmetics, foods, and consumer goods, besides medical applications. More elaborate studies are required to elucidate the mechanism of biological nanoparticles synthesis. This simple, low cost and greener method for development of AgNPs may be valuable in environmental, biotechnological and biomedical applications. Part 3 ：Novel copper and silicomolybdate (SiMO) decorated multi-walled carbon nanotubes (CuSiMO/MWCNT) have been successfully fabricated for nonenzymatic hydrogen peroxide (H2O2) detection by the electrocodeposition of copper and silicomolybdate on a MWCNT-modified electrode. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses reveal that the Cu and SiMO were successfully deposited on the MWCNT in this hybrid composite. In neutral condition, the electrode shows good activity towards H2O2 reduction with low overpotential (-0.16 V) and a current response that is 2.7–62.8 times greater than that obtained using Cu, MWCNT, Cu/MWCNT, and CuSiMO. The maximal current response is found at pH 1. Amperometric response (Eapp. = -0.1 V) indicates a linear range up to 5.2×10-3 M and with high sensitivity of 650 μA mM-1 cm-2; a low detection limit of 6.53×10-6 M (S/N = 3), and a response time of 5 s. The CuSiMO/MWCNT electrode can analyse H2O2 promising a nonenzymatic H2O2 sensor due to its low overpotential, high sensitivity, good stability, fast response, and low cost.

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37

Yu-LungShih and 施宇隆. "Fabrication and capacitor performance of 3-dimensional nickel phosphide/reduced graphene oxide nanocomposites." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/9a9qh7.

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Анотація:

碩士
國立成功大學
化學工程學系
104
This thesis concerns the fabrication and capacitor performance of three-dimensional (3-D) nickel phosphide/reduced graphene oxide nanocomposites. In the first part, 3-D nickel phosphide/reduced graphene oxide/nickel oxide on nickel foam (NP/rGO/NiO/NF) has been fabricated as a supercapacitor electrode material via the two-step electrochemical deposition. At first, nickel foam was electrochemically treated at 10 V in 0.1 M sulfuric acid to grow vertically 3D porous NiO nanosheets on the surface of Ni foam. The resulting NiO/NF showed a significantly larger capacitance than the un-treated nickel foam in 2M KOH. Secondly, the rGO/NiO/NF was fabricated by the electrochemical treatment of nickel foam in the presence of graphene oxide (GO). It was found that rGO was deposited on the surface of NiO/NF and could further increase the capacitance. The optimal electrochemical treatment time was determined to be about 10 min. Finally, nickel phosphide was electrochemically deposited on the surface of rGO/NiO/NF in the sodium hypophosphite-based aqueous solution to yield the NP/rGO/NiO/NF. It was found that the deposition of Ni2.55P led to a much higher capacitance. Also, galvanostatic charge-discharge showed that the optimal specific capacitances of 7.98 F/cm2 and 1648 F/g at the current density of 7 mA/cm2 could be obtained at the electrochemical deposition time of 30 and 10 min, respectively. After 2000 cycles at a current density of 30 mA/cm2, about 80% of specific capacitance was retained. The good electrochemical performance revealed that the NP/rGO/NiO/NF indeed could be a potential supercapacitor electrode material. In the second part, the nickel phosphide/nickel hydroxide/reduced graphene oxide (NP/Ni(OH)2/rGO) nanocomposite was fabricated as a supercapacitor electrode material via the microwave-assisted method in the ethylene glycol solution of GO, nickel sulfate and sodium hypophosphite. It was found that NP and Ni(OH)2 nanoparticles were formed simultaneously and GO was reduced to rGO whose presence was helpful for the dispersion of NP and Ni(OH)2 nanoparticles. By coating this nanocomposite on the nickel foam as the supercapacitor electrode, the specific capacitances of 1476, 1393, 1142 and 738 F/g were obtained at the current densities of 5, 7, 10 and 15 mA/cm2, respectively, in 2 M KOH electrolyte solution. This revealed that the NP/Ni(OH)2/rGO nanocomposite fabricated by the process developed in this work indeed could be used as the electrode material for supercapacitors.

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38

Qiu, Tai-jie, and 邱泰傑. "Synthesis and Characteristics of Silver Nanowires and Reduced Graphene Oxide for Transparent Conductive Films." Thesis, 2011. http://ndltd.ncl.edu.tw/handle/76937535086318555447.

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Анотація:

碩士
國立臺南大學
材料科學系碩士班
99
At present the most common material in the transparent conductive films is the tin doped indium oxide (ITO), because ITO has the high transmittance as well as good electrical property. However, ITO has certain problems, mainly centered on its scarcity of supply. Researchers have tried to develop new transparent conductive materials to replace ITO, such as carbon nanotube, graphene, and silver nanowires. In our study, the aim is to prepare and evaluate the films of silver nanowires, graphene, and their mixtures for the application as transparent conductive films. This paper will be divided into two major parts: the synthesis of silver nanowires, graphene and their hybrid materials, and the preparation and characterization of transparent conductive thin films both on the glass and flexible substrates. First, we used the polyol method to synthesize silver nanowire with sodium chloride (NaCl) as the precursor for seeds. The experimental results show that the different seeds used, the concentration of reactants, and the addition rate of silver nitrate will affect the growth characteristics of silver nanowires. SEM, UV-vis spectra and XRD have been employed to characterize the silver nanowires. This study successfully prepared silver nanowires with a diameter of 100 nm and a length of 17 μm, and the films prepared using the nanowires can have a transparency of 83 % and a sheet resistance of 11 Ω/sq. Next, the Hummer’s method is used to prepare the graphite oxide, and hydrazine is used to obtain reduced graphene oxide solution. We further varied the solid concentration and deposition density to prepare graphene thin films, and then improved the conductivity of thin films by a heat treatment step. We obtain graphene films with a transparency of 80 % and a sheet resistance of 90 kΩ/sq. And then, we mixed the silver nanowire and graphene suspensions to form hybrid materials with different ratios. The obtained films show a transmittance of 77.6 %and a sheet resistance of 17.8 Ω/sq. Finally, this study further used polyvinyl alcohol(PVA), polyamide acid(PAA) and polydimethyl siloxane(PDMS) as substrates to prepare flexible transparent conductive films. The hybrid thin films prepared on the PVA flexible substrates can have a transparency of 78.2 % and a sheet resistance of 18.8 Ω/sq.

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39

Yeh, Ming-Hsiu, and 葉名修. "Fabrication of CoO/reduced graphene oxide nanocomposites as anode materials for lithium ion battery." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/90191177761607440606.

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Анотація:

碩士
國立清華大學
生醫工程與環境科學系
102
Cobalt oxide is a promosing electrode material for lithium ion battery because of the high theoretical capacity of 715 mAh/g. In addition, cobalt oxide can proceed another electrolyte catalyzation to provide additional capacity. However, the lithium ions and electrons can not be easily moved through the CoO particles and lithium oxide byproducts when the cobalt oxide particle is large, resulting in the decrease in capacity as the current density increases. Addition of dispersing agents and the decrease in particle size of CoO can improve the transportation of lithium ions and electrons. .However, the decrease in total amounts of CoO also decrease the overall capacity of the CoO nanocomposite. In this study, a novel fabrication method has been developed to synthesize ultrafine CoO nanopaticles and then deposited onto the surface of reduced graphene oxide (CoO/rGO) to maintain the CoO amount as well as to increase the electrochemical reaction efficiency simultaneously. We used a simple and facile aqueous system to produce CoO after the heat treatment of Co3(BO3)2. Since the oxy group on the graphene surface can bond to the metal and boron element, resulting in the separation of CoO particle during the heat treatment. After optimizing the heat treatment time 1 hour in N2 gas and cobalt oxide amount 80 wt% in rGO composite, XRD showed the nano grain size lower than 10 nm, and TEM images showed that particle sizes of CoO was lower than 10 nm and can well disperse in the rGO.Because of the small particle size, The EIS showed the SEI impedance and charge transfer resistance are only 56.2 Ω.After the charge/discharge test, CoO/rGO capacity was up to 500 mAh/g when current rate was 2400 mA/g. In addition, a 60% of retention was obtaiend when the current was 150 mA/g. In the future, It can produce high loading amount and small particle of other metal or metal oxide through the metal borate decomposition. It can improve zero valent metal or metal oxide application through this method

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40

Liu, Bo-Cheng, and 劉柏成. "Preparation and Optoelectronic Properties of Transparent Conductive Hybrid Films Based on Reduced Graphene Oxide Conjugated with Silver Nanowires." Thesis, 2017. http://ndltd.ncl.edu.tw/handle/rnqed2.

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Анотація:

碩士
國立高雄應用科技大學
化學工程與材料工程系博碩士班
105
In this study, transparent conductive hybrid films (TCFs) based on reduced graphene oxide (rGO) conjugated with silver nanowires (Ag NWs) were fabricated by spin coating method and thermal treatment. Various feature parameters (i.e., line length (L), line diameter (D) and the aspect ratio (L/D)) of Ag NWs were synthesized by polyol process. Ag NW-rGO composites were further prepared by combined Ag NWs with rGO in one-step process, where rGO was prepared by modified Hummers method. Effects of reaction conditions of polyol process (i.e., stirring speed, feed rate and PVP concentration), purification methods (i.e., traditional centrifugal and selective precipitation method) and rGO layer on the feature parameters, conducting networks, sheet resistance and transmittance of Ag NW-rGO TCFs are characterized. Results showed that, at appropriate reaction conditions of polyol process, the synthesized Ag NWs exhibits the average line length (Lavg.) is 5.8 μm, the line diameter (Davg.) is 112 nm and the aspect ratio ((L/D)avg.) is 51.8. As compared with the traditional centrifugal method, the selective precipitation method provides the most of non-conductive PVP layer, which on the surface of Ag NWs, and the growing incomplete Ag NPs can be effectively removed. The reduction of the electron transfer resistance and light scattering phenomenon can be achieved by the removal of Ag NPs. The structural defects of Ag NWs networks which caused by uneven dispersion can be improved by the Ag NW-rGO conductive composites. At coating quantities 150 μL, Ag NW-rGO TCF exhibits the best optoelectronic properties, the sheet resistance is 167 Ω/sq and transmittance is 50% (at 550 nm). The optoelectronic properties of Ag NW-rGO TCF are markedly affected by their morphology and structure of Ag NW-rGO conductive networks.

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41

Hsu, Shin-Feng, and 許石鋒. "Modification of Gold Electrodes Using AuNPs/B-Cyclodextrin/Reduced Graphene Oxide Nanocomposites to Detect Simultaneously Hydroquinone and Catechol." Thesis, 2015. http://ndltd.ncl.edu.tw/handle/29419089570375317798.

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Анотація:

碩士
中國文化大學
化學系應用化學碩士班
104
A gold electrode that was modified using a nanocomposite of Au nanoparticles (AuNPs), ß-cyclodextrin (ß-CD) and a reduced graphene oxide (RGO) (AuNPs/ß-CD/RGO/Au electrode) was fabricated for use in an electrochemical sensor for the simultaneous detection of hydroquinone (HQ) and catechol (CC). The AuNPs/ß-CD/RGO nanocomposite was characterized by Fourier transform infrared spectroscopy (FTIR) and electrochemical impedance spectroscopy (EIS). The electrochemical behaviors of HQ and CC toward the AuNPs/ß-CD/RGO electrode were investigated using differential pulse voltammetry (DPV). Factors that affected the response of the AuNPs/ß-CD/RGO/Au electrode were optimized. The discrimination and sensitivity of the AuNPs/ß-CD/RGO/Au electrode were improved above those of the RGO/Au electrode by modifying it with ß-CD and AuNPs. The electrochemical sensor that was based on the AuNPs/ß-CD/RGO/Au electrode for the simultaneous detection of HQ and CC in a binary mixture had a strong response, wide working range, good linearity, low detection limit, excellent reproducibility of fabrication and excellent operational repeatability.

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42

Wang, Yi-Ting, and 王儀婷. "Fabrication of Reduced Graphene Oxide Composite and Silver Molybdate Modified Electrodes for Application to Electrochemical Sensors, Biosensors and Photocatalysis." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/2zn7sy.

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Анотація:

碩士
國立臺北科技大學
化學工程研究所
104
We have fabricated different composite modified electrdoes for application to electrochemical sensors, biosensors and photocatalysis. For instance, in the fisrt part we describe the use of a nanocomposite consisting of graphene and β-cyclodextrin (β-CD) which was used to modify a glassy carbon electrode (GCE) to serve as a matrix for immobilization of hemoglobin (Hb). The composite was characterized by scanning electron microscopy (SEM), Ultraviolet-visible spectroscopy (UV-vis) and Fourier-transform infrared (FTIR) spectroscopy. The modified electrode displays an enhanced and well-defined reversible peaks for the heme protein at a formal potential of -0.284 V (vs. Ag/AgCl). The direct electrochemistry of Hb is strongly enhanced at this modified electrode compared to electrodes not modified with graphene or β-CD. The heterogeneous electron transfer rate constant (Ks) is 3.18 ± 0.7 s‾¹ which indicates fast electron transfer. The biosensor exhibits excellent electrocatalytic activity towards the reduction of bromate, with a linear amperometric response in the 0.1 to 177 μM concentration range at a working voltage of -0.33 V. The sensitivity is 3.39 µA µM‾¹ cm‾², and the detection limit (LOD) is 33 nM. The biosensor is fast, selective, well repeatable and reproducible, and therefore represents a viable platform for sensing bromate in aqueous samples. The part II deals with the fabrication of novel and sensitive amperometric sensor for chlorpromazine (CPZ) based on the reduced graphene oxide (RGO) and polydopamine (PDA) composite modified glassy carbon electrode (GCE). The RGO@PDA composite was prepared by the electrochemical reduction of graphene oxide (GO) and PDA composite. The resulting composite was further characterized by SEM, Raman and FTIR spectroscopy. The RGO@PDA composite modified electrode shows an excellent electro-oxidation behaviour to CPZ when compared with other modified electrodes such as GO, RGO and GO@PDA. An amperometric i-t method was used for the determination of CPZ and shows that the RGO@PDA composite could detect the CPZ in the linear ranging from 0.03 to 967.6 µM. The sensor exhibits a low LOD of 0.0018 µM with the analytical sensitivity of 3.74 µA µM–1 cm–2. The RGO@PDA composite shows its high selectivity in the presence of other potentially interfering drugs such as metronidazole, phenobarbital, chlorpheniramine maleate, pyridoxine and riboflavin. The fabricated sensor has also showed an appropriate recovery towards CPZ in the pharmaceutical tablets. In the final part (Part III) we have investigated the phtocatalytic activity of as-synthesized silver molybdate (Ag2MoO4) modified electrode. The potato-like Ag2MoO4 microstructure was synthesized through simple hydrothermal treatment with the assistance of urea. The successful formation of Ag2MoO4 was confirmed by various analytical and spectroscopic techniques such as X-ray diffraction, FTIR, Raman, SEM, Energy dispersive x-ray and X-ray photoelectron spectroscopies. Furthermore, the as-prepared Ag2MoO4 was used as a photocatalyst for the degradation of ciprofloxacin (CIP) as well as an electrochemical sensor for the detection of H2O2, for the first time. The obtained UV-vis spectroscopy results demonstrate that, Ag2MoO4 had excellent reusable photocatalytic activity for the degradation CIP under Ultraviolet-light illumination possess great degradation rate of above 98% after 40 min. Moreover, the cyclic voltammetry and amperometry results revealed that Ag2MoO4 modified GCE showed good electrocatalytic performance for the detection of H2O2 with good linear range and LOD are 0.04 to 240 µM, and 0.03 µM, respectively. It also exhibit high selectivity of H2O2 in the presence of range of biological interferences such as catechol, fructose, lactose, sucrose, glucose, hydroquinone, ascorbic acid, uric acid, dopamine, and epinephrine. Hence, the potato-like Ag2MoO4 microstructure has great practical applicability for use as wastewater treatment and electrochemical detection of H2O2 in real samples.

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43

Chien-JuiLo and 羅建睿. "Fabrication of Co-based metal-organic frameworks/ N-doped reduced graphene oxide nanocomposites as bifunctional electrocatalysts for Zn-air batteries." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/cxkg4p.

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44

HO, Hsin-ping, and 何心平. "Microwave-assisted hydrothermal synthesis of tin sulfide/reduced graphene oxide nanocomposites as an anode material for high-performance lithium ion batteries." Thesis, 2014. http://ndltd.ncl.edu.tw/handle/r32726.

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Анотація:

碩士
大同大學
化學工程學系(所)
102
In this study, we used the microwave-assisted hydrothermal synthesis to prepare SnSx (x=1, 2) and SnSx/RGO (x=1, 2)composites as anode material for lithium-ion batteries. The SnS and SnS/RGO samples were carried out by a series of analysis, that the crystalline, the morphology was measured by X-ray power diffraction and scanning electron microscope, respectively, and electrochemical characteristic analysis. It can be seen that the capacity of SnS/RGO sample retain 376 mAhg-1 during 50th cycles of charge/discharge process at current density 0.2C, comparing with the capacity of the SnS sample only retain 30 mAhg-1 . This indicates that the combination tin sulfides and reduced graphene oxide of composite indeed improved the electrochemical properties and more stable cyclic performance; as indicate by AC impedance spectra. The SnS2 and SnS2/RGO samples were carried out by a series of analysis, that the crystalline, the morphology was measured by X-ray power diffraction and scanning electron microscope, respectively, and electrochemical characteristic analysis, it can be seen that the capacity of SnS2/RGO sample retain 460 mAhg-1, 342 mAhg-1 and 271 mAhg-1 during 50th cycles of charge/discharge process at different current density 0.1C, 0.5C and 1 C, respectively. In this study, we preliminary compared the experimental data of the SnS/RGO and SnS2/RGO, suggesting the charge/discharge performance of SnS2/RGO is better than SnS/RGO, but we still need to more analysis to support the thesis.

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45

CHIANG, PIN-HSUAN, and 江品璇. "Preparation and Optoelectric Properties of Few-Layer Reduced Graphene Oxide Conjugated with Self Welding Silver Nanowire Junctions as Flexible Transparent Conducting Hybrid Films." Thesis, 2018. http://ndltd.ncl.edu.tw/handle/m676a4.

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Анотація:

碩士
國立高雄應用科技大學
化學工程與材料工程系博碩士班
106
In this study, flexible transparent conducting hybrid films (TCFs) based on few layer reduced graphene oxide (FrGO) conjugated with hydrolyzed-polyethylene terephthalate (H-PET)-based self-welding (SW) commercial silver nanowires (AgNWs) were fabricated by water-bath assisted dipping coating method. H-PET-based SW-AgNW networks were controlled by the mirror silver reaction with different reaction rates and followed by dip-coated on the H-PET film. Few layer graphene oxide (FGO) were prepared by modified Hummers and low speed centrifuge method. FrGO/SW-AgNW TCFs were further prepared by reduced under sodium borohydride and followed by dip-coated on the H-PET-based SW- AgNWs. Effects of mirror silver reaction rate and FrGO layer on the conducting networks, surface morphology, sheet resistance and transmittance of FrGO/SW-AgNW TCFs are systematically studied. The interaction between AgNWs and FrGO was also further discussed. Results showed that SW-AgNW TCFs can be successfully prepared by water-bath assisted dip-coated and mirror silver reaction. As for optical and electrical characteristics analysis, the gain value of transmittance (GPS) can reach 1.88% (the transmittance is slightly increased from 76.06% to 77.49% ) which induced by the self-welding effect. However, GPS value is decreased with increasing the mirror silver reaction temperature and time. The Gain values of sheet resistance (GES) exhibit mostly negative in nature, the maximum value of GES can remark reduce to 61.06%, confirm the truth of mirror silver reaction with the excellent self-welding effect, as well GES value is also decreased with decreasing the mirror silver reaction temperature and time. Furthermore, the results revealed that FrGO/SW-AgNW TCFs can be successfully prepared by water-bath assisted dip-coated. As for optical and electrical analysis, the gain value of transmittance (GPF) can reach 1.92% (the transmittance is slightly increased from 70.80% to 72.16%). The gain value of sheet resistance (GEF) can remark reduce to 59.9% (the sheet resistance dramatically dropped from 123.6 Ω/sq to 49.5 Ω/sq). For Raman and XPS analysis, the charge transfer behavior between FrGO and SW-AgNWs is observed, which attributed to the bridging effect between FrGO and SW-AgNWs, leading to the increase the number of conductive paths in the networks.

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46

WU, CHUN-HAN, and 吳俊翰. "1. PEDOT:PSS/Reduced Graphene Oxide/Macrocyclic Zinc Complex Composites Prepared by In-situ Emulsion Polymerization for Counter Electrodes of Dye-sensitized Solar Cells2. Functional Graphene Oxide/Polystyrene Nanocomposites for Encapsulation of Perovskite Solar Cells." Thesis, 2019. http://ndltd.ncl.edu.tw/handle/f36tbt.

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Анотація:

碩士
輔仁大學
化學系
107
Dye-sensitized solar cells (DSSCs) and Perovskite solar cells (PSCs) have the advantages of simple process, high efficiency, and low cost. DSSCs are well developed, which exhibits with a more stable device performance in device efficiency. However, platinum counter electrode is relative expensive. It is one of the major issues for application of DSSCs. On the other hand, the developing of PSCs is growing rapidly with excellent power conversion efficiency. Due to the active layer of perovskite is moisture and oxygen sensitive, the stability of PSCs is still facing challenge for commercialization. Therefore, many researchers have invested in the study of stability and life of PSCs. High efficiency and thin film process PSCs have potentials for application in the future. In the first part, an in-situ emulsion polymerization was used to prepare poly (3,4-ethylenedioxythiophene): polystyrene sulfonate/reduced graphene oxide/macrocyclic zinc complex (PEDOT:PSS/rGO/macrocyclic Zn complex). To improve the dispersibility in PEDOT:PSS, GO/macrocyclic Zn complex hybrid materials were prepared by a freeze-drying method, and the hybrid materials were then annealed at 300 °C, 500 °C and 700 °C to obtain rGO/zinc nanoparticles (rGO/Zn) composite materials, which were used for preparation of PEDOT:PSS/rGO/rGO/Zn nanocomposites. Furthermore, we applied PEDOT:PSS/rGO/Zn nanocomposites to the counter electrodes of the DSSCs. The structure, thermal properties, and surface morphology of materials were identified by FT-IR, XRD, XPS, Raman, TGA, and SEM. The device performance of DSSCs for application of counter electrodes were evaluated by CV, JV Curve, EQE, and EIS analyses. The results showed that PEDOT:PSS/rGO/Zn nanocomposites were successfully applied to the counter electrodes of DSSCs, in which the device efficiency is comparable to platinum electrode, and the PEDOT:PSS/rGO/Zn-300℃ reaches the best device efficiency. In the second part, an in-situ emulsion polymerization was used to prepare polystyrene (PS) and functionalized graphene oxide (pv-GO) nanocomposites. Chemical bonding by using a vinyl-functionalized graphene (pv-GO) reacted with the vinyl group on styrene through in-situ emulsion polymerization was designed to improve the dispersion of pv-GO in PS. FT-IR, XRD, XPS, and Raman were used to identify the materials structure. TGA and DSC were used to observe the thermal properties of PS/pv-GO composites. TEM was used to identify morphologies of functional graphene oxides. Contact angle test (CA) was used to evaluate the hydrophobic properties of the composite films. In addition, PS/pv-GO nanocomposite coatings were applied for the encapsulation materials of perovskite solar cells. For example, the PS/pv-GO-2wt% nanocomposite has the best long tern stability for perovskite solar cells, which was evaluated under a stability test of 40% humidity in the atmosphere for 60 hours. As a result, the efficiency of the PS/pv-GO-2wt% encapsulated device is remain normalized 87%, which is 32% higher than unpackaged device.

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Дисертації з теми "Reduced Graphene Oxide-Silver Nanocomposite"

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