Rozprawy doktorskie na temat „Carbon Nitride”
Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych
Sprawdź 50 najlepszych rozpraw doktorskich naukowych na temat „Carbon Nitride”.
Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.
Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.
Przeglądaj rozprawy doktorskie z różnych dziedzin i twórz odpowiednie bibliografie.
Wang, Hongji. "Investigations into carbon nitrides and carbon nitride derivatives". Diss., Ludwig-Maximilians-Universität München, 2013. http://nbn-resolving.de/urn:nbn:de:bvb:19-165492.
Pełny tekst źródłaWang, Hongji [Verfasser], i Bettina [Akademischer Betreuer] Lotsch. "Investigations into carbon nitrides and carbon nitride derivatives / Hongji Wang. Betreuer: Bettina Lotsch". München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2013. http://d-nb.info/1047543478/34.
Pełny tekst źródłaMerchant, Alexander Raymond. "An investigation of carbon nitride". Thesis, The University of Sydney, 2001. http://hdl.handle.net/2123/832.
Pełny tekst źródłaMerchant, Alexander Raymond. "An investigation of carbon nitride". University of Sydney. Physics, 2001. http://hdl.handle.net/2123/832.
Pełny tekst źródłaKharlamov, A. I., M. E. Bondarenko, G. A. Kharlamova i V. V. Fomemko. "Direct Synthesis of O-doped Carbon Nitride and Oxide of Graphite-like Carbon Nitride from Melamine". Thesis, Sumy State University, 2015. http://essuir.sumdu.edu.ua/handle/123456789/42601.
Pełny tekst źródłaBerlind, Torun. "Carbon Nitride : Characterization and Protein Interactions". Doctoral thesis, Linköpings universitet, Tillämpad optik, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-19710.
Pełny tekst źródłaSchmidt, Susann. "Carbon Nitride and Carbon Fluoride Thin Films Prepared by HiPIMS". Doctoral thesis, Linköpings universitet, Tunnfilmsfysik, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-90912.
Pełny tekst źródłaNeidhardt, Jörg. "Fullerene-like carbon nitride thin solid films /". Linköping : Univ, 2004. http://www.bibl.liu.se/liupubl/disp/disp2004/tek877s.pdf.
Pełny tekst źródłaKhan, Muhammad Abdullah. "Carbon nitride based materials for heterogeneous photocatalysis". Thesis, University of Oxford, 2016. https://ora.ox.ac.uk/objects/uuid:8498a9f5-e5c8-4eda-b62d-0cd36471759c.
Pełny tekst źródłaLin, Yun Materials Science & Engineering Faculty of Science UNSW. "Contact deformation mechanism of complex carbon nitride and metal nitride based bi-layer coatings". Awarded by:University of New South Wales. Materials Science & Engineering, 2009. http://handle.unsw.edu.au/1959.4/44544.
Pełny tekst źródłaSattler, Andreas. "Investigations into s-Heptazine-Based Carbon Nitride Precursors". Diss., lmu, 2010. http://nbn-resolving.de/urn:nbn:de:bvb:19-116660.
Pełny tekst źródłaMunktell, von Fieandt Sara. "Controlled interlayer between titanium carbon-nitride and aluminiumoxide". Thesis, Uppsala universitet, Institutionen för materialkemi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-161088.
Pełny tekst źródłaWirnhier, Eva Antonie. "Solvothermal and Ionothermal Approaches to Carbon Nitride Chemistry". Diss., Ludwig-Maximilians-Universität München, 2013. http://nbn-resolving.de/urn:nbn:de:bvb:19-157389.
Pełny tekst źródłaRodil, Sandra Elizabeth. "Preparation and characterisation of carbon nitride thin films". Thesis, University of Cambridge, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.621017.
Pełny tekst źródłaMiyajima, Yoji. "Electronic properties of pulsed laser deposited amorphous carbon and carbon nitride thin films". Thesis, University of Surrey, 2007. http://epubs.surrey.ac.uk/843244/.
Pełny tekst źródłaAlmasoudi, Afaf. "Templated and activated porous carbon and carbon nitride materials for gas storage applications". Thesis, University of Nottingham, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.659191.
Pełny tekst źródłaTodi, Vinit O. "Investigation of reactively sputtered boron carbon nitride thin films". Doctoral diss., University of Central Florida, 2011. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/5069.
Pełny tekst źródłaID: 030422822; System requirements: World Wide Web browser and PDF reader.; Mode of access: World Wide Web.; Thesis (Ph.D.)--University of Central Florida, 2011.; Includes bibliographical references (p. 112-130).
Ph.D.
Doctorate
Electrical Engineering and Computer Science
Engineering and Computer Science
Nevidomskyy, Andriy Hryhorovych. "First principles calculations of carbon and boron nitride nanotubes". Thesis, University of Cambridge, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.615061.
Pełny tekst źródłaHe, Jijiang. "Preparation and photocatalysis of graphite carbon nitride based photocatalysts". Thesis, Curtin University, 2015. http://hdl.handle.net/20.500.11937/521.
Pełny tekst źródłaLees, V. J. "High pressure synthesis and characterisation of layered carbon nitride materials". Thesis, University College London (University of London), 2012. http://discovery.ucl.ac.uk/1389335/.
Pełny tekst źródłaGammon, W. Jason. "Chemical bonding in hard and elastic amorphous carbon-nitride films". W&M ScholarWorks, 2003. https://scholarworks.wm.edu/etd/1539623423.
Pełny tekst źródłaHolst, James Robert. "Synthesis of inorganic heptazine-based materials". Diss., University of Iowa, 2009. https://ir.uiowa.edu/etd/242.
Pełny tekst źródłaLiu, Mengdi. "Ta₃N₅/Polymeric g-C₃N₄ as Hybrid Photoanode for Solar Water Splitting:". Thesis, Boston College, 2018. http://hdl.handle.net/2345/bc-ir:108366.
Pełny tekst źródłaWater splitting has been recognized as a promising solution to challenges associated with the intermittent nature of solar energy for over four decades. A great deal of research has been done to develop high efficient and cost-effective catalysts for this process. Among which tantalum nitride (Ta₃N₅) has been considered as a promising candidate to serve as a good catalyst for solar water splitting based on its suitable band structure, chemical stability and high theoretical efficiency. However, this semiconductor is suffered from its special self-oxidation problem under photoelectrochemical water splitting conditions. Several key unique properties of graphitic carbon nitride (g-C₃N₄) render it an ideal choice for the protection of Ta₃N₅. In this work, Ta₃N₅/g-C₃N₄ hybrid photoanode was successfully synthesized. After addition of co-catalyst, the solar water splitting performance of this hybrid photoanode was enhanced. And this protection method could also act as a potential general protection strategy for other unstable semiconductors
Thesis (MS) — Boston College, 2018
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Chemistry
Xiao, Xiaoling, i S3060677@student rmit edu au. "Characterization of nano-structured coatings containing aluminium, aluminium-nitride and carbon". RMIT University. Applied Sciences, 2008. http://adt.lib.rmit.edu.au/adt/public/adt-VIT20081217.100453.
Pełny tekst źródłaKasap, Hatice. "Carbon nitride for solar H2 production coupled to organic chemical transformations". Thesis, University of Cambridge, 2019. https://www.repository.cam.ac.uk/handle/1810/289454.
Pełny tekst źródłaMontoya, Anthony Tristan. "Synthesis of carbon nitrides and composite photocatalyst materials". Diss., University of Iowa, 2018. https://ir.uiowa.edu/etd/6479.
Pełny tekst źródłaLotsch, Bettina Valeska. "From Molecular Building Blocks to Condensed Carbon Nitride Networks: Structure and Reactivity". Diss., [S.l.] : [s.n.], 2006. http://edoc.ub.uni-muenchen.de/archive/00006492.
Pełny tekst źródłaWang, Jing. "Development of Graphitic Carbon Nitride based Semiconductor Photocatalysts for Organic Pollutant Degradation". Doctoral thesis, KTH, Tillämpad processmetallurgi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-173216.
Pełny tekst źródłaQC 20150909
Li, Lingling. "Porphyrins, graphitic carbon nitride and their hybrids for photocatalytic solar fuel generation". HKBU Institutional Repository, 2020. https://repository.hkbu.edu.hk/etd_oa/736.
Pełny tekst źródłaMonteparo, Christopher Nicholas. "Gallium nitride sensors for hydrogen/nitrogen and hydrogen/carbon monoxide gas mixtures". [Tampa, Fla] : University of South Florida, 2009. http://purl.fcla.edu/usf/dc/et/SFE0002838.
Pełny tekst źródłaMuchharla, Baleeswaraiah. "Low Temperature Electrical Transport in 2D Layers of Graphene, Graphitic Carbon Nitride, Graphene Oxide and Boron-Nitrogen-Carbon". OpenSIUC, 2015. https://opensiuc.lib.siu.edu/dissertations/1132.
Pełny tekst źródłaZobelli, Alberto. "Electron beam generation and structure of defects in carbon and boron nitride nanotubes". Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2007. http://nbn-resolving.de/urn:nbn:de:swb:14-1197988167199-13274.
Pełny tekst źródłaMatar, M. K. H. A. "A computational study of the structure and properties of titanates and carbon nitride". Thesis, University College London (University of London), 2011. http://discovery.ucl.ac.uk/1333238/.
Pełny tekst źródłaYang, Xiaofang. "Development of hybrid surface mechanical attrition treatment : formation of carbon and nitride nanomaterials". Troyes, 2009. http://www.theses.fr/2009TROY0009.
Pełny tekst źródłaSince the development of the new technique SMAT (Surface Mechanical Attrition Treatment), great success has been achieved. The mechanical properties and the diffusion properties of materials treated by SMAT are greatly improved. Carbon nanomaterials such as carbon nanofibers (CNFs) and carbon nanotubes (CNTs) have attracted special attention due to their unique properties and potential application. Since the diffusion properties of materials have been improved after the SMAT process, a SMAT process followed by a CVD process, i. E. Hybrid SMAT, is tailored for synthesizing carbon nanomaterials in-situ on the surface of bulk metallic materials. 316L stainless steel, pure Co, pure Ni and pure Ti plate were subjected to hybrid SMAT process to synthesize carbon nanomaterials. The effects of main parameters are discussed. The products were investigated by SEM, TEM, XRD and RAMAN characterizations. Growth mechanism was proposed. The second part of work concerns the development of SMAT machine and the formation of nitride nanomaterials on bulk metallic materials. A new SMAT system that can provide various treating conditions was developed to form a thicker nanostructured surface layer. 316 stainless steel samples were subjected to the new system, treating under traction and under thermal stress respectively. The treated samples were investigated by optical micros-copy, XRD and nanoindentation. Treated samples were submitted to the nitriding process to form nitride nanomaterials. The nitride samples were investigated by optical microscopy and microhardness tester
Nguyen, Chinh Chien, i Chinh Chien Nguyen. "Novel strategies to develop efficient titanium dioxide and graphitic carbon nitride-based photocatalysts". Doctoral thesis, Université Laval, 2018. http://hdl.handle.net/20.500.11794/30378.
Pełny tekst źródłaAfin de résoudre les problèmes environnementaux et énergétiques modernes, ces dernières années ont vu le développement de catalyseurs photocataytiques capables d’utiliser la lumière solaire. En effet, les possibles applications des semiconducteurs présentant des propriétés photocatalytiques dans les domaines de la production d’hydrogène ou la dégradation de polluants organiques ont généré un grand intérêt de la part de la communauté scientifique. Actuellement, les photocatalyseurs à base de dioxyde de titane (TiO₂) et de nitrure de carbone graphitique (g-C₃N₄) sont considérés comme les matériaux les plus étudiés pour leurs faibles coûts et leurs propriétés physico-chimiques exceptionnelles. Cependant, la performance photocatalytique de ces matériaux reste encore limitée, à cause de la recombinaison rapide des porteurs de charge et et d'une absorption limitée de la lumière. En générale, malgré des caractéristiques exceptionnelles, ces matériaux ne contribuent pas significativement à la séparation de charge et l’absorption de la lumière lorsqu’ils sont produits par des méthodes conventionnelles. L'objectif de cette thèse est de développer de nouvelles voies pour la production de matériaux efficaces basés sur TiO₂ et g-C₃N₄). Nous avons d'abord préparé de la triazine (CxNy) qui fonctionne comme un co-catalyseur d'oxydation ce qui facilite la séparation des paires «électron-trou» dans le système du photocatalyseur creux de type Pt-TiO₂-CxNy. La présence simultanée de Pt et de CxNy, qui servent comme co-catalyseurs de réduction et d'oxydation, respectivement, a permis une amélioration remarquable des performances photocatalytiques du TiO₂. De plus, nous avons développé une nouvelle approche, en utilisant un procédé de combustion de sphère de carbone assisté par l’air, pour préparer du C/Pt/TiO₂ . Ce matériau possède de nombreuses propriétés uniques qui contribuent de manière significative à augmenter la séparation « électron-trou », et en conséquence, à améliorer la performance photocatalytique. Dans le but de développer un matériau qui soit capable de fonctionner sous les rayons du soleil et dans l'obscurité, nous avons développé un photocatalyseur creux à double enveloppes : le Pt-WO₃/TiO₂-Au. Ce matériau a montré non seulement une forte absorption de la lumière solaire, mais aussi une séparation des charges élevée et une haute capacité de stockage d'électrons. Par conséquent, ce type de photocatalyseurs a montré une dégradation efficace des polluants organiques, à la fois sous la lumière visible (λ ≥ 420 nm) et dans l'obscurité. En ce qui concerne le g-C₃N₄, nous avons exploité la relation entre les lacunes d’azote et les propriétés plasmoniques des nanoparticules d’or (Au). Ce type de photocatalyseur du Au/g-C₃N₄ a été préparé en présence d’alcali suivi par une post calcination. En effet, les lacunes d’azote ainsi produites permettent le renforcement des interactions entre l’or et le g-C₃N₄ et des propriétés plasmoniques de l’or. Ces caractéristiques exceptionnelles renforcent l'utilisation efficace de l’énergie solaire ainsi que la séparation des paires « électron-trou », ce qui contribuent à la performance photocatalytique pour la production d'hydrogène du photocatalyseur. Afin d’améliorer la capacité d’absorption de la lumière visible de g-C₃N₄, une nouvelle voie de synthèse dénommée « poly-alcaline » a été développée. La possibilité d’ajouter du polyéthylèneimine (PEI) et de l’hydroxyde de potassium (KOH) pour générer de nombreux centres lacunaires en azote ainsi que des groupes hydroxyles dans la structure du matériau, a été explorée afin d’optimiser l’efficacité du matériau. De telles modifications ont démontré leurs capacités à réduire la bande interdite et à provoquer plus facilement la séparation de charges améliorant ainsi les propriétés photocatalytiques du photocatalyseur vis-à-vis de la production d’hydrogène. Cette méthode ouvre donc une nouvelle voie d’avenir pour préparer des photocatalyseurs nanocomposites efficaces possédant à la fois, une forte d’absorption de la lumière et une bonne séparation de charges.
The utilization of solar light-driven photocatalysts has emerged as a potential approach to deal with the serious current energy and environmental issues. Over the past decades, semiconductor-based photocatalysis has attracted an increasing attention for diverse applications including hydrogen production and the decomposition of organic pollutants. Currently, titanium dioxide (TiO₂) and graphitic carbon nitride (g-C₃N₄)-based photocatalysts have been considered as the most investigated materials because of their low cost, outstanding physical and chemical properties. However, their photocatalytic performances are still moderate owing to the fast charge carrier recombination and limited light absorption. The main target of the research presented in this thesis is to develop novel routes to prepare efficient materials based on TiO₂ and g-C₃N₄. These materials possess prominent features, which contribute to address the fast charge separation and light absorption problems. We firstly have prepared triazine (CxNy) acting as an oxidation co-catalyst, which efficiently facilitates electron-hole separation in a Pt-TiO₂-CxNy hollow photocatalyst system. The co-existence of Pt and CxNy functioning as the reduction and oxidation co-catalysts, respectively, has remarkably enhanced the photocatalytic performance of TiO₂. Next, we have also developed a new approach employing the air- assisted carbon sphere combustion process in preparing C/Pt/TiO₂. This material possesses many salient properties that significantly boost the electron-hole separation leading to enhanced photocatalytic performance. In an attempt to design a material that can operate under sunlight and in darkness, we have introduced Pt-WO₃/TiO₂-Au double shell hollow photocatalyst. The material has shown not only strong solar light absorption but also efficient charge separation and electron storage capacity. As a result, this type of photocatalyst exhibits a high activity performance for the degradation of organic pollutants both under visible light (λ ≥ 420 nm) and in the dark. Regarding to g-C₃N₄, we have explored the relationship between nitrogen vacancies and the plasmonic properties of Au nanoparticles employing alkali associated with the post-calcination method to prepare Au/g-C₃N₄. In fact, the produced nitrogen vacancies in the structure of g-C₃N₄ essentially enhance the interaction at Au/g-C₃N₄ interface and the plasmonic properties of Au nanoparticles. These outstanding features contribute to enhance the utilization of solar light and electron-hole separation that prompt the photocatalytic performance towards hydrogen production. Finally, we have employed a novel poly-alkali route to prepare a strong visible light absorption photocatalyst-based g-C₃N₄. The co-existence of PEI and KOH, which induces numerous nitrogen vacancies and incorporated hydroxyl groups in the structure of the resulted material, has been explored for the first time. These modifications have been proved to narrow the bandgap and facilitate the charge separation leading to enhance the solar light-driven hydrogen production. This method also opens up a new approach to prepare efficient nanocomposite photocatalysts possessing both strong light absorption and good charge separation.
The utilization of solar light-driven photocatalysts has emerged as a potential approach to deal with the serious current energy and environmental issues. Over the past decades, semiconductor-based photocatalysis has attracted an increasing attention for diverse applications including hydrogen production and the decomposition of organic pollutants. Currently, titanium dioxide (TiO₂) and graphitic carbon nitride (g-C₃N₄)-based photocatalysts have been considered as the most investigated materials because of their low cost, outstanding physical and chemical properties. However, their photocatalytic performances are still moderate owing to the fast charge carrier recombination and limited light absorption. The main target of the research presented in this thesis is to develop novel routes to prepare efficient materials based on TiO₂ and g-C₃N₄. These materials possess prominent features, which contribute to address the fast charge separation and light absorption problems. We firstly have prepared triazine (CxNy) acting as an oxidation co-catalyst, which efficiently facilitates electron-hole separation in a Pt-TiO₂-CxNy hollow photocatalyst system. The co-existence of Pt and CxNy functioning as the reduction and oxidation co-catalysts, respectively, has remarkably enhanced the photocatalytic performance of TiO₂. Next, we have also developed a new approach employing the air- assisted carbon sphere combustion process in preparing C/Pt/TiO₂. This material possesses many salient properties that significantly boost the electron-hole separation leading to enhanced photocatalytic performance. In an attempt to design a material that can operate under sunlight and in darkness, we have introduced Pt-WO₃/TiO₂-Au double shell hollow photocatalyst. The material has shown not only strong solar light absorption but also efficient charge separation and electron storage capacity. As a result, this type of photocatalyst exhibits a high activity performance for the degradation of organic pollutants both under visible light (λ ≥ 420 nm) and in the dark. Regarding to g-C₃N₄, we have explored the relationship between nitrogen vacancies and the plasmonic properties of Au nanoparticles employing alkali associated with the post-calcination method to prepare Au/g-C₃N₄. In fact, the produced nitrogen vacancies in the structure of g-C₃N₄ essentially enhance the interaction at Au/g-C₃N₄ interface and the plasmonic properties of Au nanoparticles. These outstanding features contribute to enhance the utilization of solar light and electron-hole separation that prompt the photocatalytic performance towards hydrogen production. Finally, we have employed a novel poly-alkali route to prepare a strong visible light absorption photocatalyst-based g-C₃N₄. The co-existence of PEI and KOH, which induces numerous nitrogen vacancies and incorporated hydroxyl groups in the structure of the resulted material, has been explored for the first time. These modifications have been proved to narrow the bandgap and facilitate the charge separation leading to enhance the solar light-driven hydrogen production. This method also opens up a new approach to prepare efficient nanocomposite photocatalysts possessing both strong light absorption and good charge separation.
Kumru, Baris [Verfasser], i Markus [Akademischer Betreuer] Antonietti. "Utilization of graphitic carbon nitride in dispersed media / Baris Kumru ; Betreuer: Markus Antonietti". Potsdam : Universität Potsdam, 2018. http://d-nb.info/1219078034/34.
Pełny tekst źródłaAdekoya, Oluwatobi. "Design and Synthesis of Graphitic Carbon Nitride (g-C3N4) Based Materials for Rechargeable Batteries". Thesis, Griffith University, 2020. http://hdl.handle.net/10072/401444.
Pełny tekst źródłaThesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environment and Sc
Science, Environment, Engineering and Technology
Full Text
Zambon, Adrien. "Modèles chimiques du nitrure de carbone graphitique : lien structure-propriétés". Thesis, Université Grenoble Alpes (ComUE), 2015. http://www.theses.fr/2015GREAV024/document.
Pełny tekst źródłaGraphitic carbon nitride (gCN) is an organic semi-conductor which has lately attracted a lot of attention when its photocatalytic properties were highlighted for water splitting. It has been recently shown to be based on the heptazine core, but its three-dimensional structure remains elusive. This is first due to its poor solubility which prevents the use of classical characterization techniques, and second to the fact that changes in synthesis experimental conditions (precursors, temperature…) yield different materials. The synthesis of tailored and well-defined molecular models would therefore certainly be of great interest to better understand the structure-properties relationship of this material. This is the aim of the work presented in this manuscript. The reactivity of cyameluryl chloride, a monomeric precursor, has been studied, and a protocol for a quantitative selective substitution by aliphatic secondary amines has been determined. The use of deprotonation by a strong base or thermal treatment yielded two dimers and one linear trimer. The oligomers have been characterized by several technique (X-ray diffraction, NMR, IR, UV-vis absorption, emission, electrochemistry), and the obtained data were in close agreement to the ones observed in DFT. As a rule of thumb, a decrease of the electronic transition energies is observed for an increasing chain length. The application of extrapolation methods to the experimental data suggests that oligomers are relevant molecular models for gCN
Chiguma, Jasper. "Conducting polymer nanocomposites loaded with nanotubes and fibers for electrical and thermal applications". Diss., Online access via UMI:, 2009.
Znajdź pełny tekst źródłaLiljenberg, Marcus. "Poly(triazine imide) : Growing Larger Crystallites of CrystallineCarbon Nitride and Understanding Their Dissolution". Thesis, Uppsala universitet, Institutionen för kemi - Ångström, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-377151.
Pełny tekst źródłaWirnhier, Eva Antonie [Verfasser], i Wolfgang [Akademischer Betreuer] Schnick. "Solvothermal and Ionothermal Approaches to Carbon Nitride Chemistry / Eva Antonie Wirnhier. Betreuer: Wolfgang Schnick". München : Universitätsbibliothek der Ludwig-Maximilians-Universität, 2013. http://d-nb.info/1036143899/34.
Pełny tekst źródłaLELLO, BRUNO CAVALCANTE DI. "SYNTHESIS OF GALLIUM NITRIDE POWDER FROM GAS-SOLID REACTION USING CARBON AS REDUCING AGENT". PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2002. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=4002@1.
Pełny tekst źródłaO nitreto de gálio (GaN) é um dos mais interessantes e promissores materiais para aplicação em dispositivos óptico- eletrônicos. GaN pode ser usado para a fabricação de diodos e lasers azuis. O desenvolvimento deste tipo de material está relacionado com três campos principais: 1) deposição de camadas de GaN cristalino; 2) produção de nano- filamentos a partir de reações confinadas no interior de nanotubos de carbono; 3) síntese de GaN em pó por diferentes métodos químicos. Recentemente, novas técnicas de deposição adotaram a sublimação de pós de GaN como fonte de gálio para a produção de nanofilamentos de GaN, filmes finos ou cristais. Estes métodos de sublimação mostram a necessidade do emprego de pós de GaN. No presente trabalho, é apresentada uma nova rota para a produção de pós de GaN a partir da reação gás-sólido entre Ga2O3 e NH3(g) utilizando o carbono como agente redutor no interior de um novo tipo de reator, disposto verticalmente. A partir desta rota obteve-se pós de GaN com conversões aproximadamente de 100% e com estrutura cristalina hexagonal. A quantidade de GaN obtida variou de acordo com os parâmetros experimentais adotados. Através de uma análise estatística foi possível determinar a influência da temperatura, razão molar de carbono/Ga2O3 e do tempo experimental sobre a taxa de produção de GaN.
It is well known that gallium nitride (GaN) is one of the most interesting and promising materials for optoelectronic devices. GaN can be used for manufacturing blue light- emitting diodes and lasers. Development of this material is concerned with three main areas 1) deposition of GaN crystalline layers onto different substrates; 2) manufacturing of GaN nanorods from chemical reactions in the confined spaces provided by carbon nanotubes; 3) synthesis of GaN powders by different chemical methods. Recently, new deposition techniques have adopted sublimation of GaN powders as gallium source to produce GaN nanorods, thin films or bulk crystals. These sublimation methods rely on the supply of GaN powders. This thesis presents a new route to produce GaN powder from gas-solid chemical reaction between Ga2O3 and NH3 using carbon as reducing agent in a new reactor design. The GaN powder obtained from this route possesses a hexagonal crystal structure and was found to correspond to almost 100% conversion of Ga2O3. The amount of GaN present in the powders varied with experimental parameters. A statistical analysis showed the influence of temperature, carbon/Ga2O3 ratio and experimental time on the production of GaN powder.
Kayani, Asghar Nawaz. "Deposition and characterization of Diamond-like carbon films with and without hydrogen and nitrogen". Ohio University / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1080935389.
Pełny tekst źródłaBojdys, Michael Janus. "On new allotropes and nanostructures of carbon nitrides". Phd thesis, Universität Potsdam, 2009. http://opus.kobv.de/ubp/volltexte/2010/4123/.
Pełny tekst źródłaDie vorliegende Arbeit befasst sich mit der Synthese und Charakterisierung neuer Allotropen und Nanostrukturen von Karbonitriden und berührt einige ihrer möglichen Anwendungen. Alle gezeigten, ausgedehnten, kovalent verbundenen Karbonitridgerüste wurden in einem ionothermalen Syntheseprozess – einer Hochtemperaturbehandlung in einem eutektischen Salzgemisch als ungewöhnlichem Lösungsmittel – aus einfachen Präkursormolkülen erzeugt. Der Kondensationsmechanismus folgt einer temperaturinduzierten Deaminierung und Bildung einer ausgedehnten, aromatischen Einheit; des dreifach substituierten Heptazines. Die Dissertation folgt vier übergreifenden Themen, beginnend mit der Einleitung in Karbonitridsysteme und der Suche nach einem Material, welches einzig aus Kohlenstoff und Stickstoff aufgebaut ist – einer Suche, die 1834 mit den Beobachtungen Justus von Liebigs „über einige Stickstoffverbindungen“ begann. Der erste Abschnitt zeigt die erfolgreiche Synthese von graphitischem Karbonitrid (g-C3N4); einer Spezies, welche auf Schichten hexagonal angeordneter s-Heptazineinheiten beruht, die durch kovalente Bindungen zwischen C- und N-Atomen zusammengehalten werden, und welche in einer graphitischen, verschobenen Art und Weise gestapelt sind. Der zweite Abschnitt berührt die Vielfalt von Salzschmelzensystemen, die für die Ionothermalsynthese geeignet sind und zeigt auf, dass die bloße Veränderung der Salzschmelze eine andere Kristallphase des graphitischen Karbonitrides ergibt – das g-C3N4-mod2. Im dritten Abschnitt wird vom Graphit bekannte Interkallationschemie auf das g-C3N4 angewendet, um eine Kalliuminterkallationsverbindung des graphitischen Karbonitirdes zu erhalten (K(C6N8)3). Diese Verbindung kann in Analogie zum graphitischen System leicht exfoliiert werden, um Bündel von Karbonitridnanoschichten zu erhalten, und weist darüberhinaus interessante optische Eigenschaften auf. Der vierte und letzte Abschnitt handelt von der Einführung von Aryl- und Biphenylbrücken in das Karbonitridmaterial durch rationale Synthese der Präkursormoleküle. Diese ergeben die heptazinbasierten Frameworks, HBF-1 und HBF-2 – zwei kovalente, organische Gerüste.
羅時勳. "Field emission properties of carbon and carbon nitride films". Thesis, 2001. http://ndltd.ncl.edu.tw/handle/38080595835680656139.
Pełny tekst źródła國立臺北科技大學
機電整合研究所
89
This study investigates the feasibility of DLC and C-N film as the FED candidate materials. Thin films deposited by R. F. Sputtering method, home-made nano-diamonds target, and inlet the C-N reaction gases. Results show that the film structure appeared column type, accompanied the vacuum pressure increasing the column structure deteriorating, and the film became flat, smooth, and dense finally. The DLC thin film of column structure conducted by hydrogen plasma etching, the column became thin, and the threshold electric field also became lower. Besides, the result showed that the threshold electric field decreased in contained nitrogen carbon film and the carbon nitride film, which suggested that the sub-energy band formed when nitrogen doped into films. The lowest threshold electric field 12.81 V/μm, the biggest current density 1.35 mA/cm2 in this study were obtained when the films were growing above the silicon pyramid array and Au as the interlayer. In conclusion, the results suggested that the field emission characteristics are boosted when adding the metal interlayer, inletting the nitrogen gas and performing the silicon pyramid array.
Corral, Erica Lorrane. "Single-walled carbon nanotube-silicon nitride composites". Thesis, 2005. http://hdl.handle.net/1911/18753.
Pełny tekst źródłaWu, Jing-Hsing, i 吳進興. "Synthesis and Characterization of Carbon Nitride Nanotube". Thesis, 2005. http://ndltd.ncl.edu.tw/handle/35414113969490095617.
Pełny tekst źródła國立交通大學
應用化學系所
93
The thesis are divided into two parts. In the first part, we used 2,4,6-trichloro-1,3,5-triazine as the precursor to react with sodium which have been achieved by decomposing sodium hydrate at 623 K. At a low reaction temperature of 623 K, carbon nitride nanosphere、porous carbon nitride material and byproduct sodium chloride, would be produced. In the second part, we used porous anodic alumina oxide as the template. At 623 K, 2,4,6-trichloro-1,3,5-triazine reacted with the reactive template, which formed from thermally decomposing NaH on AAO, generated carbon nitride nanotube and byproduct sodium chloride inside the template channels. Well-ordered carbon nitride nanotube bundles with a high content of nitrogen were isolated after the sodium chloride and template were removed by deionized water and 48% HF, respectively. The diameter of the carbon nitride nanotubes was 300 nm, the length was 60 μm, and the wall thickness was 50 nm.
Li, Jie-An, i 李捷安. "Visible-light responsive graphitic carbon nitride photocatalysts". Thesis, 2018. http://ndltd.ncl.edu.tw/handle/2jyb9u.
Pełny tekst źródła國立中興大學
環境工程學系所
106
A visible-light-driven graphitic carbon nitride/reduced graphene oxide/α-Sulfur composite (CNRGOS8) was synthesized as efficient photocatalysts for environmental applications. The photocatalytic reactivity of the fabricated CNRGOS8 was determined by the degradation of Rhodamine B (RhB) and tetracycline (TC). The effects of pH, mixed ratio of catalysts, dosage of photocatalyst were optimized, and the reaction kinetics and reaction pathway were studied. The results indicated the optimized pH values for RhB and TC degradation was 3 and 7, respectively. In addition, no deterioration of the efficiency was found for CNRGOS8 (70:5:25) after 5 cycles of operation. Such a result was indicative of a prolonged lifetime of the CNRGOS8 (70:5:25). With probing by the scavengers, 2-Propanol (·OH capture reagent), benzoquinone (O2•- capture reagent) and sodium oxalate (h+ capture reagent), the major reactive species were identified as superoxide radicals and hydroxyl radicals. The abundant natural organic matter such as humic acid (HA) oftentimes coexists with the pollutants in the aquatic environment, which may affect the efficiency and alter reaction pathways of photodegradation of the pollutants. An enhanced electron transfer and reactive oxide species production were found for CNRGOS8 (70:5:25) in the presence of humic acid. However, the overall removal efficiency of the pollutants was suppressed due to the competition between CNRGOS8 (70:5:25) and the coexisting HA for the active sites.
Chen, Ying-Hsun, i 陳盈薰. "A Novel Procedure for Syntheses of Carbon and Carbon Nitride Nanotube". Thesis, 2003. http://ndltd.ncl.edu.tw/handle/09180356823695541853.
Pełny tekst źródła國立交通大學
應用化學系
91
The reaction between hexachlorocyclopentadiene (C5Cl6) and Na, which have been achieved by decomposing NaH thermally, can afford diversified morphologies of nano-sized carbon at 623 K, including urchin-like spheres, hollow spheres with cubic core as well as tubulate structures. The formation of cubic-cored hollow spheres and tubulate structure might be caused by NaCl by-product. The formation of diversified morphologies may be attributed to heterogeneous contact of the two reactants. Besides, we successfully developed a new strategy for formation of an reactive template by thermally decomposing NaH on AAO, which can react with carbonhalides to produce carbon tubes. First of all, reacting the reactive template with C5Cl6 at 623 K generates carbon nanotubes inside the template channels. Well-ordered carbon nanotube bundles ( diameter of 300 nm, length of 60 μm, wall thickness of 20 nm ) were isolated after the template was removed by 48% HF. Lowering the reaction temperate to 473 K led to the formation of carbon nanotubes with porous wall. The pore size distribution data, caculated from nitrogen desorption branch of isotherms by BJH ( Barret-Joyner-Halenda ) method, showed that the mesoporous walls were uniform with narrow pore size distribution centered at 4 nm. Moreover, well-ordered CNx nanotubes with a high content of nitrogen ( x ∼17% ) were carried out by reacting pentachloropyridine ( C5NCl5 ) with the reactive template at 623 K. The diameter of the CNx nanotubes was 300 nm, the length was 60μm, and the wall thickness was 20 nm.
Ho, Sin-Yi, i 何信逸. "Molybdenum Oxide / Graphitic Carbon Nitride Composites for Photocatalytic Reduction of Carbon Dioxide". Thesis, 2018. http://ndltd.ncl.edu.tw/handle/6xmg7k.
Pełny tekst źródła逢甲大學
化學工程學系
106
In this study, molybdenum oxides with various oxidation states were decorated on two-dimensional graphitic carbon nitride (gCN) to enhance the photocatlytic activity of CO2 reduction under visible light irradiation and to correlate the characteristics of photocatalysts to the efficiency of CO2 conversion. Part 1: Preparation and Properties of Molybdenum Trioxide / Graphitic Carbon Nitride Composite for Photocatalysis Molybdemum trioxide/graphitic carbon nitride was prepared by calcination and hydrothermal method. Ammonium molybdate tetrahydrate was the precursor of molybdenum and melamine was for gCN. Molybdenum trioxide (MoO3) was obtained by hydrothermal method (210 °C) and graphitic carbon nitride was by calcination method (450 °C) at Air or Ar. XRD result confirmed the crystal phase of MoO3 and characteristic peaks of gCN. SEM images confirmed the morphology of MoO3 and gCN. TEM images presented the distribution of MoO3. A significant red shift, compared to pure MoO3, revealed from UV-VIS spectra of samples with the presence of gCN. After calcination under Ar, some MoO3 reduced to MoO2 as evidenced from ESCA results of MoO3-gCN-Ar and thus increased photocatalytic activity. Photocatalytic reduction of CO2 showed MoO3-gCN-Ar (8 W, 254 nm) could successfully convert CO2 into CO, and the yield of CO was 0.067 mol/gcat. Part 2: Preparation and Properties of Molybdenum Oxide Quantum Dots / Graphitic Carbon Nitride Composite for Photocatalysis In order to further improve the photocatalytic activity of CO2, molybdenum oxide quantum dots/graphitic carbon nitride composites (MoOx-QDs-gCN) were prepared in the second part of this study. Molybdenum oxide quantum dots were prepared by hydrothermal method (80 °C) using molybdenum powder as the precursor. The melamine was used as a precursor to prepare graphitic carbon nitride (gCN) by calcining at 500 °C and 550 °C under air atmosphere. The obtained molybdenum oxide quantum dots were mixed with gCN and then calcined at 300 °C. XRD, ESCA and EDX results confirmed that the catalyst contained molybdenum oxide with various oxidation states on gCN. TEM images showed after calcination graphitic carbon nitride still mentain their characteristic structure. A significant red shift of the absorption edge of MoOx-QDs-gCN, compared to gCN, was observed from UV-VIS spectra. Carbon dioxide photocatalytic reduction results showed MoOx-0.3gCN (8 W, 254 nm) had the best conversion yield of CO and the yield of CO was 0.418 mol/gcat. Part 3:In-Situ Preparation and Properties of Molybdenum Oxide / Graphitic Carbon Nitride Composite for Photocatalysis In the third part of this study, in-situ preparation of molybdenum oxide (MoOx) on gCN was attemped to improve the interaction of gCN and MoOx. Thermal condensation method was applied to fabricate graphitic carbon nitride(gCN). Different amounts of molybdenum disulfide (MoS2) were dissolved with hydrogen peroxide solution, followed by the addition of gCN. Strong oxidation of hydrogen peroxide with molybdenum disulfide was ulilized to replace the sulfur atoms of molybdenum disulfide to oxygen atoms. The presence of nitrogen active sites on gCN surface has electronic affinity with molybdenum ions. After the deposition of molybdenum oxide particals on gCN, the remained sulfur ions were removed by neutralization by alkali. After centrifugated and washed, we could obtain the composite photocatalysts and named XMS-0.1CN, where X indicates the volume of MoS2. The results of XPS-Mo3d confirmed that the photocatalyst 30MS-0.1CN had the highest ratio of Mo4+ (compared with the other photocatalyst). The appearance of Mo4+ could improve the charge transport capacity and promote photocatalytic activity. The UV-Vis and Tauc Plot analysis results were shown that the in-situ synthesized photocatalyst had a red shift of the absorption edge compared with pure gCN and the band-gap was narrowed by 0.1 to 0.2 eV. The results of PL spactrum analysis showed that the photoluminescence intensity of in-situ prepared photocatalyst was lower than that from that emitted from pure gCN. This result indicated that molybdenum oxide after in-situ growth could effectively reduce the recombination efficiency of photogenerated electron-holes. In the photocatalytic reduction of carbon dioxide, carbon monoxide was the only successful conversion product. 30MS-0.1CN had the highest conversion yield, 3.937 mol/gcat, as the highest Mo4+ ratio was estimated by ESCA. This study showed that the in-situ growth of the photocatalyst was indeed effective at improving photocatalytic activity compared to pure gCN.