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Kimura, Keisaku, i Thalappil Pradeep. "Functional noble metal nanoparticle superlattices grown at interfaces". Physical Chemistry Chemical Physics 13, nr 43 (2011): 19214. http://dx.doi.org/10.1039/c1cp22279a.
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Borodaenko, Yulia, Evgeniia Khairullina, Aleksandra Levshakova, Alexander Shmalko, Ilya Tumkin, Stanislav Gurbatov, Aleksandr Mironenko i in. "Noble-Metal Nanoparticle-Embedded Silicon Nanogratings via Single-Step Laser-Induced Periodic Surface Structuring". Nanomaterials 13, nr 8 (7.04.2023): 1300. http://dx.doi.org/10.3390/nano13081300.
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Here, we show that direct femtosecond laser nanostructuring of monocrystalline Si wafers in aqueous solutions containing noble-metal precursors (such as palladium dichloride, potassium hexachloroplatinate, and silver nitrate) allows for the creation of nanogratings decorated with mono- (Pd, Pt, and Ag) and bimetallic (Pd-Pt) nanoparticles (NPs). Multi-pulse femtosecond-laser exposure was found to drive periodically modulated ablation of the Si surface, while simultaneous thermal-induced reduction of the metal-containing acids and salts causes local surface morphology decoration with functional noble metal NPs. The orientation of the formed Si nanogratings with their nano-trenches decorated with noble-metal NPs can be controlled by the polarization direction of the incident laser beam, which was justified, for both linearly polarized Gaussian and radially (azimuthally) polarized vector beams. The produced hybrid NP-decorated Si nanogratings with a radially varying nano-trench orientation demonstrated anisotropic antireflection performance, as well as photocatalytic activity, probed by SERS tracing of the paraaminothiophenol-to-dimercaptoazobenzene transformation. The developed single-step maskless procedure of liquid-phase Si surface nanostructuring that proceeds simultaneously with the localized reduction of noble-metal precursors allows for the formation of hybrid Si nanogratings with controllable amounts of mono- and bimetallic NPs, paving the way toward applications in heterogeneous catalysis, optical detection, light harvesting, and sensing.
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Abbasi, Zeeshan, Wajeeha Saeed, Syed Marifat Shah, Sohail Anjum Shahzad, Muhammad Bilal, Abdul Faheem Khan i Ahson Jabbar Shaikh. "Binding efficiency of functional groups towards noble metal surfaces using graphene oxide – metal nanoparticle hybrids". Colloids and Surfaces A: Physicochemical and Engineering Aspects 611 (luty 2021): 125858. http://dx.doi.org/10.1016/j.colsurfa.2020.125858.
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Cheng, Kang, Luc C. J. Smulders, Lars I. van der Wal, Jogchum Oenema, Johannes D. Meeldijk, Nienke L. Visser, Glenn Sunley i in. "Maximizing noble metal utilization in solid catalysts by control of nanoparticle location". Science 377, nr 6602 (8.07.2022): 204–8. http://dx.doi.org/10.1126/science.abn8289.
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Maximizing the utilization of noble metals is crucial for applications such as catalysis. We found that the minimum loading of platinum for optimal performance in the hydroconversion of n -alkanes for industrially relevant bifunctional catalysts could be reduced by a factor of 10 or more through the rational arranging of functional sites at the nanoscale. Intentionally depositing traces of platinum nanoparticles on the alumina binder or the outer surface of zeolite crystals, instead of inside the zeolite crystals, enhanced isomer selectivity without compromising activity. Separation between platinum and zeolite acid sites preserved the metal and acid functions by limiting micropore blockage by metal clusters and enhancing access to metal sites. Reduced platinum nanoparticles were more active than platinum single atoms strongly bonded to the alumina binder.
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Li, Yunxing, Yuhua Hu, Sunjie Ye, Yan Wu, Cheng Yang i Likui Wang. "Functional polyaniline-assisted decoration of polystyrene microspheres with noble metal nanoparticles and their enhanced catalytic properties". New Journal of Chemistry 40, nr 12 (2016): 10398–405. http://dx.doi.org/10.1039/c6nj02200f.
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Lin, Xia, Fan Zou, Xinzhu Chen i Bin Tang. "Functional modification of Nylon fabrics based on noble metal nanoparticles". IOP Conference Series: Materials Science and Engineering 231 (wrzesień 2017): 012175. http://dx.doi.org/10.1088/1757-899x/231/1/012175.
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Zou, Yiming, Ronn Goei, Su-Ann Ong, Amanda Jiamin ONG, Jingfeng Huang i Alfred Iing Yoong TOK. "Development of Core-Shell Rh@Pt and Rh@Ir Nanoparticle Thin Film Using Atomic Layer Deposition for HER Electrocatalysis Applications". Processes 10, nr 5 (18.05.2022): 1008. http://dx.doi.org/10.3390/pr10051008.
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The efficiency of hydrogen gas generation via electrochemical water splitting has been mostly limited by the availability of electrocatalyst materials that require lower overpotentials during the redox reaction. Noble metals have been used extensively as electrocatalysts due to their high activity and low overpotentials. However, the use of single noble metal electrocatalyst is limited due to atomic aggregation caused by its inherent high surface energy, which results in poor structural stability, and, hence, poor electrocatalytic performance and long-term stability. In addition, using noble metals as electrocatalysts also causes the cost to be unnecessarily high. These limitations in noble metal electrocatalysts could be enhanced by combining two noble metals in a core-shell structure (e.g., Rh@Ir) as a thin film over a base substrate. This could significantly enhance electrocatalytic activity due to the following: (1) the modification of the electronic structure, which increases electrical conductivity; (2) the optimization of the adsorption energy; and (3) the introduction of new active sites in the core-shell noble metal structure. The current state-of-the-art employs physical vapor deposition (PVD) or other deposition techniques to fabricate core-shell noble metals on flat 2D substrates. This method does not allow 3D substrates with high surface areas to be used. In the present work, atomic layer deposition (ALD) was used to fabricate nanoparticle thin films of Rh@Ir and Rh@Pt in a core-shell structure on glassy carbon electrodes. ALD enables the fabrication of nanoparticle thin film on three-dimensional substrates (a 2D functional film on a 3D substrate), resulting in a significantly increased surface area for a catalytic reaction to take place; hence, improving the performance of electrocatalysis. The Rh@Pt (with an overpotential of 139 mV and a Tafel slope of 84.8 mV/dec) and Rh@Ir (with an overpotential of 169 mV and a Tafel slope of 112 mV/dec) core-shell electrocatalyst exhibited a better electrocatalytic performances compared to the single metal Rh electrocatalyst (with an overpotential of 300 mV and a Tafel slope of 190 mV/dec). These represented a 54% and a 44% improvement in performance, respectively, illustrating the advantages of core-shell thin film nanostructures in enhancing the catalytic performance of an electrocatalyst. Both electrocatalysts also exhibited good long-term stability in the harsh acidic electrolyte conditions when subjected to chronopotentiometry studies.
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Bosch-Navarro, Concha, Jonathan P. Rourke i Neil R. Wilson. "Controlled electrochemical and electroless deposition of noble metal nanoparticles on graphene". RSC Advances 6, nr 77 (2016): 73790–96. http://dx.doi.org/10.1039/c6ra14836k.
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Electrodeposition is a powerful tool for forming functional composites with graphene. Indeed, noble metal nanoparticles can be directly electrodeposited onto graphene, and their size and number density can be easily controlled.
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Hughes, Zak E., i Tiffany R. Walsh. "Non-covalent adsorption of amino acid analogues on noble-metal nanoparticles: influence of edges and vertices". Physical Chemistry Chemical Physics 18, nr 26 (2016): 17525–33. http://dx.doi.org/10.1039/c6cp02323a.
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First-principles calculations on nanoscale-sized noble metal nanoparticles demonstrate that planes, edges and vertices show different noncovalent adsorption propensities depending on the adsorbate functional group.
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An, Xingda, Ayan Majumder, James McNeely, Jialing Yang, Taranee Puri, Zhiliang He, Taimeng Liang, John K. Snyder, John E. Straub i Björn M. Reinhard. "Interfacial hydration determines orientational and functional dimorphism of sterol-derived Raman tags in lipid-coated nanoparticles". Proceedings of the National Academy of Sciences 118, nr 33 (13.08.2021): e2105913118. http://dx.doi.org/10.1073/pnas.2105913118.
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Lipid-coated noble metal nanoparticles (L-NPs) combine the biomimetic surface properties of a self-assembled lipid membrane with the plasmonic properties of a nanoparticle (NP) core. In this work, we investigate derivatives of cholesterol, which can be found in high concentrations in biological membranes, and other terpenoids, as tunable, synthetic platforms to functionalize L-NPs. Side chains of different length and polarity, with a terminal alkyne group as Raman label, are introduced into cholesterol and betulin frameworks. The synthesized tags are shown to coexist in two conformations in the lipid layer of the L-NPs, identified as “head-out” and “head-in” orientations, whose relative ratio is determined by their interactions with the lipid–water hydrogen-bonding network. The orientational dimorphism of the tags introduces orthogonal functionalities into the NP surface for selective targeting and plasmon-enhanced Raman sensing, which is utilized for the identification and Raman imaging of epidermal growth factor receptor–overexpressing cancer cells.
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Pandey, Prem C., i Govind Pandey. "3-Aminopropyltrimethoxysilane Mediated Controlled Synthesis of Functional Noble Metal Nanoparticles and Its Multi-Metallic Analogues in the Presence of Small Organic Reducing Agents for Selective Application". MRS Advances 3, nr 15-16 (2018): 789–801. http://dx.doi.org/10.1557/adv.2018.93.
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ABSTRACTSynthesis of functional noble metal nanoparticles (AuNPs, AgNPs, and PdNPs) and its multi-metallic analogues have received greater attentions for selective applications. The selective applications of the these nanoparticles essentially requires the processability of as synthesized nanoparticles in the medium of desired polarity index that manifest the potential exploration of nanomaterial based design in targeted area. The use of conventional reducing and stabilizing agents during routine synthesis of such nanoparticles are not suitable with the system of practical significance and require additional reagents that limit the optimum activity of nanomaterial in targeted design. According there is a challenging issue in the synthesis of noble metal nanoparticles that allow the controlled synthesis of such nanoparticles involving same starting material with option to control the processability of as generated nanomaterial in the system of desired polarity index. The present report is focused on such challenging issues. We have found that 3-aminopropyltrimethoxysilane (3-APTMS) capped noble metal cations can be precisely converted into respective monometallic, bimetallic and trimetallic analogues and can be made processable in water at one end having controlled option to reversed the processability of the same in the toluene as a function of small organic reducing agents. The organic reducing agents not only convert 3-APTMS-capped noble cations into respective nanoparticles but also control the processability of the as generated nanoparticles in the systems of desired polarity index. The similar process also allows the synthesis of function bimetallic and tri-metallic nanoparticles. The role of cyclohexanone, formaldehyde and acetone in the presence of 3-APTMS is reported.
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Pandey, Prem C., i Govind Pandey. "Synthesis and characterization of bimetallic noble metal nanoparticles for biomedical applications". MRS Advances 1, nr 11 (2016): 681–91. http://dx.doi.org/10.1557/adv.2016.47.
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ABSTRACTWe report herein a facile approach to synthesize processable bimetallic nanoparticles (Pd-Au/AuPd/Ag-Au/Au-Ag) decorated Prussian blue nanocomposite (PB-AgNP). The presence of cyclohexanone/formaldehyde facilitates the formation of functional bimetallic nanoparticles from 3-aminopropyltrimethoxysilane (3-APTMS) capped desired ratio of hetero noble metal ions. The use of 3-APTMS and cyclohexanone also enables the synthesis of polycrystalline Prussian blue nanoparticles (PBNPs). As synthesized PBNPs, Pd-Au/Au-Pd/Ag-Au/Au-Ag enable the formation of nano-structured composites displaying better catalytic activity than that recorded with natural enzyme. The nanomaterials have been characterized by Uv-Vis, FT-IR and Transmission Electron Microscopy (TEM) with following major findings: (1) 3-APTMS capped noble metal ions in the presence of suitable organic reducing agents i.e.; 3 glycidoxypropyltrimethoxysilane (GPTMS), cyclohexanone and formaldehyde; are converted into respective nanoparticles under ambient conditions, (2) the time course of synthesis and dispersibility of the nanoparticles are found as a function of organic reducing agents, (3) the use of formaldehyde and cyclohexanone in place of GPTMS with 3-APTMS outclasses the other two in imparting better stability of amphiphilic nanoparticles with reduced silanol content, (4) simultaneous synthesis of bimetallic nanoparticles under desired ratio of palladium/gold and silver/ gold cations are recorded, (5) the nanoparticles made from the use of 3-APTMS and cyclohexanone enable the formation of homogeneous nanocomposite with PBNP as peroxidase mimetic representing potential substitute of peroxidase enzyme. The peroxidase mimetic ability has been found to vary as a function of 3-APTMS concentration revealing the potential role of functional metal nanoparticles in bioanalytical applications.
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Liu, Shuanghong, Guan Huang, Jiefei Wang, Jianshuai Bao, Mengyue Wang, Yaqun Wei, Yong Zhong i Feng Bai. "Noble Metal Nanoparticle-Loaded Porphyrin Hexagonal Submicrowires Composites (M-HW): Photocatalytic Synthesis and Enhanced Photocatalytic Activity". Nanomaterials 13, nr 4 (8.02.2023): 660. http://dx.doi.org/10.3390/nano13040660.
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Surface plasmon resonance (SPR) photocatalysts have attracted considerable attention because of their strong absorption capacity of visible light and enhanced photogenic carrier separation efficiency. However, the separate production of metal nanoparticles (NPs) and semiconductors limits the photogenic charge transfer. As one of the most promising organic photocatalysts, porphyrin self-assemblies with a long-range ordered structure-enhance electron transfer. In this study, plasmonic noble metal-based porphyrin hexagonal submicrowires composites (M-HW) loaded with platinum (Pt), silver (Ag), gold (Au), and palladium (Pd) NPs were synthesized through a simple in situ photocatalytic method. Homogeneous and uniformly distributed metal particles on the M-HW composites enhanced the catalytic or chemical properties of the organic functional nanostructures. Under the same loading of metal NPs, the methyl orange photocatalytic degradation efficiency of Ag-HW [kAg-HW (0.043 min−1)] composite was three times higher than that of HW, followed by Pt-HW [kPt-HW (0.0417 min−1)], Au-HW [kAu-HW (0.0312 min−1)], and Pd-HW [kPd-HW (0.0198 min−1)]. However, the rhodamine B (RhB) and eosin B photocatalytic degradations of Pt-HW were 4 times and 2.6 times those of HW, respectively. Finally, the SPR-induced electron injection, trapping, and recombination processes of the M-HW system were investigated. These results showed that M-HW plasmonic photocatalysts exhibited excellent photocatalytic performances, making them promising materials for photodegrading organic pollutants.
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Shafey, Asmaa Mohamed El. "Green synthesis of metal and metal oxide nanoparticles from plant leaf extracts and their applications: A review". Green Processing and Synthesis 9, nr 1 (18.06.2020): 304–39. http://dx.doi.org/10.1515/gps-2020-0031.
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AbstractMetal nanoparticles (MNPs) and metal oxide nanoparticles (MONPs) are used in numerous fields. The new nano-based entities are being strongly generated and incorporated into everyday personal care products, cosmetics, medicines, drug delivery, and clothing to impact industrial and manufacturing sectors, which means that nanomaterials commercialization and nano-assisted device will continuously grow. They can be prepared by many methods such as green synthesis and the conventional chemical synthesis methods. Green synthesis includes infinite accession to produce MNPs and MONPs with demanding properties. The structure–function relationships between nanomaterials and key information for life cycle evaluation lead to the production of high execution nanoscale materials that are gentle and environmentally friendly. Majority of plants have features as sustainable and renewable suppliers compared with microbes and enzymes, as they have the ability to pick up almost 75% of the light energy and transform it into chemical energy, contain chemicals like antioxidants and sugars, and play fundamental roles in the manufacture of nanoparticles. Plants considered the main factory for the green synthesis of MNPs and MONPs, and until now, different plant species have been used to study this, but the determined conditions should be taken into consideration to execute this preparation. In this study, we focus on the biosynthesis procedures to synthesize MNPs and MONPs, including comparison between green synthesis and the classical chemistry methods as well as the several new orientation of green synthesis of nanoparticles from different plant parts, especially plant leaf extracts. Plants with reducing compounds is the preferred choice for the synthesis of noble metals – metal ions can be reduced to the corresponding metals in the absence of any other chemicals under microwave irradiation conditions using benign solvent, water. Noble metals such as gold (Au), silver (Ag), platinum (Pt), and palladium (Pd) and other metals such as copper (Cu) and nickel (Ni), which are characterized by their optical, electronic, mechanical, magnetic, and chemical properties, leading to different technological applications. Plants with numerous reducing agents are suitable candidates for the manufacture of noble MNPs. The main purpose of this research is to give a background on green nanotechnology prospective evolution, pertinent concerns appeared related to the green synthesis of metal and metal oxide from plant extracts, nanoparticle formation mechanism, and the importance of flavonoids, vitamin B2, ascorbic acid (vitamin C), and phenolic compounds in the MNP and MONP production. The traditional sorghum beers are produced in many countries in Africa, but diversity in the production process may depend on the geographic localization. These beers are very rich in calories; B-group vitamins including thiamine, folic acid, riboflavin, and nicotinic acid; and essential amino acids such as lysine. However, the Western beers are more attractive than the traditional sorghum beers. The traditional sorghum beers have poor hygienic quality, organoleptic variations, and shorter shelf life compared with the Western beers. Many research studies on traditional sorghum beers have been carried out and documented in several African countries, especially the microbiological and biochemical properties, the technologies used in the manufacture processes, and synthetic characteristics of African traditional sorghum beers (ikigage, merissa, doro, dolo, pito, amgba, and tchoukoutou). The excellent resources for the production of greener biomaterials are plants and considerable advances have been achieved in many fields such as biotechnology and gene transfer. The manufactured biological nanomaterials have a great application in the pharmaceutical industry such as novel pharmaceuticals preparation, drug delivery personification procedures, and production of functional nanodevices.
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MUNIZ-MIRANDA, Francesco. "Computational Approaches to the Electronic Properties of Noble Metal Nanoclusters Protected by Organic Ligands". Nanomaterials 11, nr 9 (16.09.2021): 2409. http://dx.doi.org/10.3390/nano11092409.
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Organometallic nanoparticles composed by metal cores with sizes under two nanometers covered with organic capping ligands exhibit intermediate properties between those of atoms and molecules on one side, and those of larger metal nanoparticles on the other. In fact, these particles do not show a peculiar metallic behavior, characterized by plasmon resonances, but instead they have nonvanishing band-gaps, more along molecular optical properties. As a consequence, they are suitable to be described and investigated by computational approaches such as those used in quantum chemistry, for instance those based on the time-dependent density functional theory (TD-DFT). Here, I present a short review of the research performed from 2014 onward at the University of Modena and Reggio Emilia (Italy) on the TD-DFT interpretation of the electronic spectra of different organic-protected gold and/or silver nanoclusters.
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IONI, Yulia V. "NANOPARTICLES OF NOBLE METALS ON THE SURFACE OF GRAPHENE FLAKES". Periódico Tchê Química 17, nr 36 (20.12.2020): 1199–211. http://dx.doi.org/10.52571/ptq.v17.n36.2020.1215_periodico36_pgs_1199_1211.pdf.
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Carbon is a spread element that has many different reaction combinations. Obtaining new composite materials based on nanoparticles is a very actual and perspective topic because nanoparticles possess unique properties. These properties are retained and even amplified when nanoparticles are located in various matrixes. Furthermore, nowadays, the creation of graphene-based composites and graphene-related structures is a promising area of synthesis of composite nanomaterials. Previous research has determined that graphene has a unique set of electrophysical, thermal, optical, and mechanical properties. In this study, the synthesis of nanocomposites representing nanoparticles of noble metals (Au, Pd, Rh) on the surface of graphene flakes were carried out, and the study of their composition, structure, physical and chemical properties, and possible applications in catalysis. The immobilization of nanoparticles on the surface of graphene oxide and graphene was developed, and the original method of synthesis of nanocomposite noble metal nanoparticles on the graphene flakes surface using supercritical isopropanol as a reduction agent for the transformation of graphene oxide into graphene was created. The study of physical and chemical properties of the obtained nanocomposites and results of the study of obtained nanocomposites as catalysts for model organic reactions of cross-coupling and hydroformylation showed that it is possible to create the graphene-based nanostructures as effective functional nanomaterials. Research on the synthesis of graphene compounds and its unique physical properties form a promising direction in the chemistry and physics of new inorganic functional materials. The resulting nanocomposites can be used in such branches as electrodes for LEDs and solar cells, field-effect transistors, supercapacitors, sensors, fuel cells.
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Pandey, P. C., Shubhangi Shukla, Govind Pandey i Roger J. Narayan. "Organotrialkoxysilane-mediated synthesis of functional noble metal nanoparticles and their bimetallic for electrochemical recognition of L-tryptophan". MRS Advances 5, nr 46-47 (2020): 2429–44. http://dx.doi.org/10.1557/adv.2020.305.
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AbstractEffective and pH-sensitive electrochemical monitoring of L-tryptophan using noble metal nanocatalysts was evaluated in this study. This work examined the electrocatalytic influence of nanoparticles on the oxidation of amino acids with the variation of pH in working media. Bimetallic nanohybrids of palladium, silver, and gold (e.g., Pd/Ag and Pd/Au nanoparticles) were processed using organofunctionalized alkoxysilanes (3-aminopropyltrimethoxysilane (3-APTMS) and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane (EETMOS)) via a sequential reduction pathway. Transmission electron microscopy (TEM) demonstrated the role of the alkoxysilanes in determining the size of the nanoparticles and the distribution of metals in the core-shell configuration. The cluster-like morphology of PdNPs was remodeled to form bimetallic nanomaterials (Pd-AuNPs and Pd-AgNPs) with a core-shell structure. Enhancement in the electrooxidation behavior was shown to depend on the nanomaterial and the pH of the medium. The Pd-AgNPs modified electrode exhibited high sensitivity and selectivity, with characteristic amplification in cathodic peak current at lower oxidation potentials (0.659 V, 0.782 V, and 0.890 V at pH values 4, 7, and 9, respectively) due to its greater stability. Differential pulse voltammetric (DPV) scans were recorded over a wide range of concentrations from 0.1 μM to 1000μM; the Pd-AgNPs modified electrode showed the lowest limit of detection of 0.1μM at pH 4, 0.5 μM at pH 7, and 0.5 μM at pH 9.
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Sun, Jian, Jiafeng Yu, Qingxiang Ma, Fanqiong Meng, Xiaoxuan Wei, Yannan Sun i Noritatsu Tsubaki. "Freezing copper as a noble metal–like catalyst for preliminary hydrogenation". Science Advances 4, nr 12 (grudzień 2018): eaau3275. http://dx.doi.org/10.1126/sciadv.aau3275.
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The control of product distribution in a multistep catalytic selective hydrogenation reaction is challenging. For instance, the deep hydrogenation of dimethyl oxalate (DMO) is inclined to proceed over Cu/SiO2 catalysts because of inevitable coexistence of Cu+ and Cu0, leading to hard acquisition of the preliminary hydrogenation product, methyl glycolate (MG). Here, the oriented DMO hydrogenation into MG is achieved over the sputtering (SP) Cu/SiO2 catalysts with a selectivity of more than 87% via freezing Cu in a zero-valence state. Our density functional theory calculation results revealed that Cu0 is the active site of the preliminary hydrogenation step, selectively converting DMO to MG via •H addition, while Cu+ is a key factor for deep hydrogenation. The prominent Coster-Kronig transition enhancement is observed over SP-Cu/SiO2 from Auger spectra, indicating that the electron density of inner shells in Cu atoms is enhanced by high-energy argon plasma bombardment during the SP process. Thus, the “penetration effect” of outermost electrons could also be enhanced, making these Cu nanoparticles exhibit high oxidation resistance ability and present noble metal–like behaviors as Au or Ag. Therefore, the regulation of Cu chemical properties by changing the electron structure is a feasible strategy to control the hydrogenation products, inspiring the rational design of selective hydrogenation catalysts.
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Le, Van Thuan, Ngoc Nhu Quynh Ngu, Tan Phat Chau, Thi Dung Nguyen, Van Toan Nguyen, Thi Lan Huong Nguyen, Xuan Thang Cao i Van-Dat Doan. "Silver and Gold Nanoparticles from Limnophila rugosa Leaves: Biosynthesis, Characterization, and Catalytic Activity in Reduction of Nitrophenols". Journal of Nanomaterials 2021 (20.05.2021): 1–11. http://dx.doi.org/10.1155/2021/5571663.
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This study describes a simple green method for the synthesis of Limnophila rugosa leaf-extract-capped silver and gold nanoparticles without using any expensive toxic reductant or stabilizer. The noble metal nanoparticles were characterized by Fourier transform infrared (FTIR) microscopy, powder X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray analysis (EDX), high-resolution transmission electron microscopy (HR-TEM), selected area electron diffraction (SAED), and dynamic light scattering (DLS) method. It has been found that the biosynthesized silver and gold nanoparticles are nearly spherical in shape with a mean particle size distribution of 87.5 nm and 122.8 nm, respectively. XRD and SAED patterns confirmed the crystalline nanostructure of the metal nanoparticles. FTIR spectra revealed the functional groups of biomolecules presented in the extract possibly responsible for reducing metallic ions and stabilizing formed nanoparticles. The biosynthesized metal nanoparticles have potential application in catalysis. Compared to previous reports, Limnophila rugosa leaf-extract-capped silver and gold nanoparticles exhibited a good catalytic activity in the reduction of several derivatives of nitrophenols including 1,4-dinitrobenzene, 2-nitrophenol, 3-nitrophenol, and 4-nitrophenol.
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Dzhagan, Volodymyr, Oleksandr Smirnov, Mariia Kovalenko, Nazar Mazur, Oleksandr Hreshchuk, Nataliya Taran, Svitlana Plokhovska i in. "Spectroscopic Study of Phytosynthesized Ag Nanoparticles and Their Activity as SERS Substrate". Chemosensors 10, nr 4 (29.03.2022): 129. http://dx.doi.org/10.3390/chemosensors10040129.
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The affordable and scalable synthesis of noble metal nanoparticles that are biocompatible without additional functionalization steps has been a growing field of research, stimulated by numerous prospective applications of these NPs. In the case of phytosynthesized or biogenic noble metal NPs, the mechanism of NP stabilization by biomolecules contained in each particular plant extract or living organism determines the possible applications of these NPs. In this work, we investigated Ag NPs synthesized in water with plant extracts of common toothwort (Lathraea squamaria) and two species of pepper (Capsicum annuum and Capsicum chinense). From FTIR and XPS, we drew conclusions about the composition of the functional groups and molecules that stabilize NPs in each extract, such as polysaccharide compounds (pectins, cellulose, glycosides and phenolic acids). Distinct characteristic IR features of amide I and amide II proteins were observed, which are common in plant extracts, while features of amide III were not distinctly observed in our extracts. A Raman spectroscopy study revealed weak own-SERS activity of the biomolecules of the extract and high efficiency of the NPs in the enhancement of “external” analytes, such as dyes and antibodies. This is the first report of the efficient SERS application of phytosynthesized Ag NPs.
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Dorovskikh, Svetlana I., Evgeniia S. Vikulova, David S. Sergeevichev, Tatiana Ya Guselnikova, Alexander A. Zheravin, Dmitriy A. Nasimov, Maria B. Vasilieva i in. "Biological Studies of New Implant Materials Based on Carbon and Polymer Carriers with Film Heterostructures Containing Noble Metals". Biomedicines 10, nr 9 (8.09.2022): 2230. http://dx.doi.org/10.3390/biomedicines10092230.
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This paper presents pioneering results on the evaluation of noble metal film hetero-structures to improve some functional characteristics of carbon-based implant materials: carbon-composite material (CCM) and carbon-fiber-reinforced polyetheretherketone (CFR-PEEK). Metal-organic chemical vapor deposition (MOCVD) was successfully applied to the deposition of Ir, Pt, and PtIr films on these carriers. A noble metal layer as thin as 1 µm provided clear X-ray imaging of 1–2.5 mm thick CFR-PEEK samples. The coated and pristine CCM and CFR-PEEK samples were further surface-modified with Au and Ag nanoparticles (NPs) through MOCVD and physical vapor deposition (PVD) processes, respectively. The composition and microstructural features, the NPs sizes, and surface concentrations were determined. In vitro biological studies included tests for cytotoxicity and antibacterial properties. A series of samples were selected for subcutaneous implantation in rats (up to 3 months) and histological studies. The bimetallic PtIr-based heterostructures showed no cytotoxicity in vitro, but were less biocompatible due to a dense two-layered fibrous capsule. AuNP heterostructures on CFR-PEEK promoted cell proliferation in vitro and exhibited a strong inhibition of bacterial growth (p < 0.05) and high in vitro biocompatibility, especially Au/Ir structures. AgNP heterostructures showed a more pronounced antibacterial effect, while their in vivo biocompatibility was better than that of the pristine CFR-PEEK, but worse than that of AuNP heterostructures.
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Wang, Maofei, Masaki Tsukamoto, Vladimir G. Sergeyev i Anatoly Zinchenko. "Metal Ions Sensing by Biodots Prepared from DNA, RNA, and Nucleotides". Biosensors 11, nr 9 (13.09.2021): 333. http://dx.doi.org/10.3390/bios11090333.
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Nucleic acids that exhibit a high affinity toward noble and transition metal ions have attracted growing attention in the fields of metal ion sensing, toxic metal ion removal, and the construction of functional metal nanostructures. In this study, fluorescent nanoparticles (biodots) were synthesized from DNA, RNA, and RNA nucleotides (AMP, GMP, UMP, and CMP) using a hydrothermal (HT) method, in order to study their metal ion sensing characteristics. The fluorescent properties of biodots differ markedly between those prepared from purine and pyrimidine nucleobases. All biodots demonstrate a high sensitivity to the presence of mercury cations (Hg2+), while biodots prepared from DNA, RNA, and guanosine monophosphate (GMP) are also sensitive to Ag+ and Cu2+ ions, but to a lesser extent. The obtained results show that biodots inherit the metal ion recognition properties of nucleobases, while the nucleobase composition of biodot precursors affects metal ion sensitivity and selectivity. A linear response of biodot fluorescence to Hg2+ concentration in solution was observed for AMP and GMP biodots in the range 0–250 μM, which can be used for the analytic detection of mercury ion concentration. A facile paper strip test was also developed that allows visual detection of mercury ions in solutions.
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Graczyk, Anna, Roza Pawlowska, Dominika Jedrzejczyk i Arkadiusz Chworos. "Gold Nanoparticles in Conjunction with Nucleic Acids as a Modern Molecular System for Cellular Delivery". Molecules 25, nr 1 (3.01.2020): 204. http://dx.doi.org/10.3390/molecules25010204.
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Development of nanotechnology has become prominent in many fields, such as medicine, electronics, production of materials, and modern drugs. Nanomaterials and nanoparticles have gained recognition owing to the unique biochemical and physical properties. Considering cellular application, it is speculated that nanoparticles can transfer through cell membranes following different routes exclusively owing to their size (up to 100 nm) and surface functionalities. Nanoparticles have capacity to enter cells by themselves but also to carry other molecules through the lipid bilayer. This quality has been utilized in cellular delivery of substances like small chemical drugs or nucleic acids. Different nanoparticles including lipids, silica, and metal nanoparticles have been exploited in conjugation with nucleic acids. However, the noble metal nanoparticles create an alternative, out of which gold nanoparticles (AuNP) are the most common. The hybrids of DNA or RNA and metal nanoparticles can be employed for functional assemblies for variety of applications in medicine, diagnostics or nano-electronics by means of biomarkers, specific imaging probes, or gene expression regulatory function. In this review, we focus on the conjugates of gold nanoparticles and nucleic acids in the view of their potential application for cellular delivery and biomedicine. This review covers the current advances in the nanotechnology of DNA and RNA-AuNP conjugates and their potential applications. We emphasize the crucial role of metal nanoparticles in the nanotechnology of nucleic acids and explore the role of such conjugates in the biological systems. Finally, mechanisms guiding the process of cellular intake, essential for delivery of modern therapeutics, will be discussed.
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Chifor, Emilian, Ion Bordeianu, Crina Anastasescu, Jose Maria Calderon-Moreno, Veronica Bratan, Diana-Ioana Eftemie, Mihai Anastasescu i in. "Bioactive Coatings Based on Nanostructured TiO2 Modified with Noble Metal Nanoparticles and Lysozyme for Ti Dental Implants". Nanomaterials 12, nr 18 (14.09.2022): 3186. http://dx.doi.org/10.3390/nano12183186.
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This work presents the synthesis of nanostructured TiO2 modified with noble metal nanoparticles (Au, Ag) and lysozyme and coated on titanium foil. Moreover, the specific structural and functional properties of the resulting inorganic and hybrid materials were explored. The purpose of this study was to identify the key parameters for developing engineered coatings on titanium foil appropriate for efficient dental implants with intrinsic antibacterial activity. TiO2 nanoparticles obtained using the sol–gel method were deposited on Ti foil and modified with Au/Ag nanoparticles. Morphological and structural investigations (scanning electron and atomic force microscopies, X-ray diffraction, photoluminescence, and UV–Vis spectroscopies) were carried out for the characterization of the resulting inorganic coatings. In order to modify their antibacterial activity, which is essential for safe dental implants, the following aspects were investigated: (a) singlet oxygen (1O2) generation by inorganic coatings exposed to visible light irradiation; (b) the antibacterial behavior emphasized by titania-based coatings deposited on titanium foil (TiO2/Ti foil; Au–TiO2/Ti foil, Ag–TiO2/Ti foil); (c) the lysozyme bioactivity on the microbial substrate (Micrococcus lysodeicticus) after its adsorption on inorganic surfaces (Lys/TiO2/Ti foil; Lys/Au–TiO2/Ti foil, Lys/Ag–TiO2/Ti foil); (d) the enzymatic activity of the above-mentioned hybrids materials for the hydrolysis reaction of a synthetic organic substrate usually used for monitoring the lysozyme biocatalytic activity, namely, 4-Methylumbelliferyl β-D-N,N′,N″-triacetylchitotrioside [4-MU-β- (GlcNAc)3]. This was evaluated by identifying the presence of a fluorescent reaction product, 7-hydroxy-4-metyl coumarin (4-methylumbelliferone).
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Gandhiraman, Ram P., Gowri Manickam, Laura Kerr, Chandra K. Dixit, Colin Doyle, David E. Williams i Stephen Daniels. "Plasma-Fabricated Surface Plasmon Resonance Chip for Biosensing". Australian Journal of Chemistry 68, nr 3 (2015): 447. http://dx.doi.org/10.1071/ch14324.
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This work reports the fabrication of a biosensing chip surface designed for plasmonic detection, and features a layer of noble metal nanoparticles encapsulated as a sandwich within amine-functionalized polysiloxane layers formed by plasma-enhanced chemical vapour deposition. The collective surface plasmon resonance (CSPR) phenomenon characteristic of a dense particle layer is demonstrated for encapsulated gold nanoparticles of different diameters. Biomolecular immobilization is carried out through the amine functional groups that are part of the encapsulating layer. The detection of biomolecular binding events at the sensor surface is demonstrated both by a shift in resonance wavelength at constant angle of incidence using SPR-enhanced spectroscopic ellipsometry and by detecting the angular shift in resonance in a commercial SPR instrument (Biacore®). Taken with other results, this work shows how a complete SPR chip can be assembled by a rapid sequence of operations in a single plasma chamber.
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Ungerer, Marietjie J., i Nora H. De Leeuw. "Computational Insights into Ru, Pd and Pt fcc Nano-Catalysts from Density Functional Theory Calculations: The Influence of Long-Range Dispersion Corrections". Catalysts 12, nr 10 (21.10.2022): 1287. http://dx.doi.org/10.3390/catal12101287.
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Ruthenium, palladium and platinum fall within the group of noble metals that are widely used in catalysis, especially for the electrocatalytic production of hydrogen. The dominant phase of the bulk Ru metal is hexagonal close-packed (hcp), which has been studied extensively. However, significantly less attention has been paid to the face-centred cubic (fcc) phases, which have been observed in nanoparticles. In this study, we have carried out density functional theory calculations with long-range dispersion corrections [DFT-D2, DFT-D3 and DFT-D3-(BJ)] to investigate the lattice parameters, surface energies and work functions of the (001), (011) and (111) surfaces of Ru, Pd and Pt in the fcc phase. When investigating the surface properties of the three metals, we observed that the DFT-D2 method generally underestimated the lattice parameters by up to 2.2% for Pt and 2.8% for Ru. The surface energies followed the observed trend (111) < (001) < (011) for both Ru and Pd with all three methods, which is comparable to experimental data. For Pt the same trend was observed with DFT-D2 and DFT-D3(BJ), but it deviated to Pt (111) < Pt (011) < Pt (001) for the DFT-D3 method. DFT-D2 overestimated the surface energies for all three Miller Indexes by 82%, 73%, and 60%, when compared to experimental values. The best correlation for the surface energies was obtained with the DFT-D3 and DFT-D3(BJ) methods, both of which have deviate by less than 15% deviation for all surfaces with respect to experiment. The work function followed the trend of Φ (111) < Φ (001) < Φ (011) for all three metals and calculated by all three methods. Five different types of Ru, Pd and Pt nanoparticles were considered, including icosahedral, decahedral, cuboctahedral, cubic and spherical particles of different sizes. The bulk, surface and nanoparticle calculations showed that the DFT-D2 method for Pt overestimated the exchange-correlation, leading to higher energy values that can be contributed erroneously to a more stable structure. The calculations showed that as soon as the surface-to-bulk ratio > 1, the energy per atom resembles bulk energy values.
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Borodaenko, Yulia, Stanislav Gurbatov, Evgeny Modin, Aleksandr Chepak, Mikhail Tutov, Aleksandr Mironenko i Aleksandr Kuchmizhak. "A Laser-Printed Surface-Enhanced Photoluminescence Sensor for the Sub-Nanomolar Optical Detection of Mercury in Water". Chemosensors 11, nr 5 (20.05.2023): 307. http://dx.doi.org/10.3390/chemosensors11050307.
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Here, we report a novel, easy-to-implement scalable single-step procedure for the fabrication of a solid-state surface-enhanced photoluminescence (SEPL) sensor via the direct femtosecond (fs) laser patterning of monocrystalline Si wafers placed under the layer of functionalizing solution simultaneously containing a metal salt precursor (AgNO3) and a photoluminescent probe (d114). Such laser processing creates periodically modulated micro- and nanostructures decorated with Ag nanoparticles on the Si surface, which effectively adsorbs and retains the photoluminescent sensor layer. The SEPL effect stimulated by the micro- and nanostructures formed on the Si surface localizing pump radiation within the near-surface layer and surface plasmons supported by the decorating Ag nanoparticles is responsible for the intense optical sensory response modulated by a small amount of analyte species. The produced SEPL sensor operating within a fluidic device was found to detect sub-nanomolar concentrations of Hg2+ in water which is two orders of magnitude lower compared to this molecular probe sensitivity in solution. The fabrication technique is upscalable, inexpensive, and flexible regarding the ability to the control surface nano-morphology, the amount and type of loading noble-metal nanoparticles, as well as the type of molecular probe. This opens up pathways for the on-demand development of various multi-functional chemosensing platforms with expanded functionality.
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Guan, Keke, Qing Zhu, Zhong Huang, Zhenxia Huang, Haijun Zhang, Junkai Wang, Quanli Jia i Shaowei Zhang. "Excellent Catalytic Performance of ISOBAM Stabilized Co/Fe Colloidal Catalysts toward KBH4 Hydrolysis". Nanomaterials 12, nr 17 (30.08.2022): 2998. http://dx.doi.org/10.3390/nano12172998.
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Recently, developing a cost-effective and high-performance catalyst is regarded as an urgent priority for hydrogen generation technology. In this work, ISOBAM-104 stabilized Co/Fe colloidal catalysts were prepared via a co-reduction method and used for the hydrogen generation from KBH4 hydrolysis. The obtained ISOBAM-104 stabilized Co10Fe90 colloidal catalysts exhibit an outstanding catalytic activity of 37,900 mL-H2 min−1 g-Co−1, which is far higher than that of Fe or Co monometallic nanoparticles (MNPs). The apparent activation energy (Ea) of the as-prepared Co10Fe90 colloidal catalysts is only 14.6 ± 0.7 kJ mol−1, which is much lower than that of previous reported noble metal-based catalysts. The X-ray photoelectron spectroscopy results and density functional theory calculations demonstrate that the electron transfer between Fe and Co atoms is beneficial for the catalytic hydrolysis of KBH4.
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Yamanaka, Nobutaka, i Shogo Shimazu. "Selective Hydrogenation Properties of Ni-Based Bimetallic Catalysts". Eng 3, nr 1 (11.01.2022): 60–77. http://dx.doi.org/10.3390/eng3010006.
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Metallic Ni shows high activity for a variety of hydrogenation reactions due to its intrinsically high capability for H2 activation, but it suffers from low chemoselectivity for target products when two or more reactive functional groups are present on one molecule. Modification by other metals changes the geometric and electronic structures of the monometallic Ni catalyst, providing an opportunity to design Ni-based bimetallic catalysts with improved activity, chemoselectivity, and durability. In this review, the hydrogenation properties of these catalysts are described starting from the typical methods of preparing Ni-based bimetallic nanoparticles. In most cases, the reasons for the enhanced catalysis are discussed based on the geometric and electronic effects. This review provides new insights into the development of more efficient and well-structured non-noble metal-based bimetallic catalytic systems for chemoselective hydrogenation reactions.
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Devi Asem, Satyavama, i Warjeet S. Laitonjam. "Green synthesis of Ag nanoparticles using aqueous extract of Kaempferia galanga Linn. (Zingiberaceae) rhizomes". JOURNAL OF ADVANCES IN CHEMISTRY 7, nr 2 (17.12.2011): 1324–30. http://dx.doi.org/10.24297/jac.v7i2.2361.
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Green synthesis of noble metal nanoparticles (NPs) is a vast developing area of research. In the present study, silver nanoparticles (Ag-NPs) were rapidly synthesized by treating silver ions through a simple and green synthetic route using water extract of the rhizomes of Kaempferia galanga Linn.(KG), which acted simultaneously as a reductant and stabilizer. The reaction process was monitored using ultraviolet–visible (UV-Vis) spectroscopy. The EPR spectra of AgKG NPs was found to be confined in a single line which showed the presence of an unpaired electron indicating of Ag in neutral state at room temperature. The size and morphology of AgNPs recorded by Scanning electron microscopy (SEM) were further confirmed by transmission electron microscopy (TEM) and selected area electron diffraction (SAED). The formation of AgNPs is evidenced by the appearance of signatory brown colour of the solution. FT-IR spectrum indicates the presence of different functional groups in capping the nanoparticles with K. galanga. Average size range estimated from our studies is 2 to 4 nm. It consists of a spherical like particles.
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Seco Gudiña, Román, Susana Yáñez Vilar, Manuel González Gómez, Zulema Vargas Osorio, María de la Fuente, Yolanda Piñeiro Redondo, Rafael López i José Rivas. "Versatile Mesoporous Nanoparticles for Cell Applications". Journal of Nanoscience and Nanotechnology 21, nr 5 (1.05.2021): 2824–33. http://dx.doi.org/10.1166/jnn.2021.19054.
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Mesoporous silica nanostructures are emerging as a promising platform able to deal with challenges of many different applications in fields such as biomedicine and nanotechnology. The versatile physical and functional properties of these materials like high specific surface area, ordered porosity, chemical stability under temperature and pH variations, and biocompatible performance, offers new approaches to many biomedical applications ranging from drug delivery systems to biosensing, cell applications and tissue engineering. Their morphology, size and textural properties can be easily tailored by means of chemical control, giving rise to a variety of nanostructures with hexagonal (SBA15, MCM41) or cubic (SBA16) arrangement of channels and pore size ranging from 1.3 to 10 nm. Based on the versatility of their silane surface, a plethora of hybrid mesoporous matrices can be prepared incorporating new functionalities like contrast enhancement for magnetic resonance imaging, magnetic/plasmonic hyperthermia, drug delivery or cell applications by the simple grafting of superparamagnetic metal oxides (Fe3O4, transition metal ferrites) nanoparticles, noble metal (Au, Ag) nanoparticles, fluorescent moieties (fluorescein, rhodamine) or biological agents (mAb, mRNA, etc). The goal of this work is to present the development, by a facile soft template method, of size tailored mesoporous silica nanospheres from 20 to 350 nm (by means of chemical control), and highlight its versatility for surface grafting (with rhodamine and polydopamine) and their biological compatibility and efficient uptake by cultured HeLa cells. The combined, physicochemical and biological, properties indicate that MSNs are good candidates for cell tagging, gene transfer or targeted therapies.
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Bhatti, Adeel Liaquat, Umair Aftab, Aneela Tahira, Muhammad Ishaq Abro, Riaz Hussain Mari, Muhammad Kashif Samoon, Muhammad Hassan Aghem, Nek Muhammad Shaikh, Abdul Qayoom Mugheri i Zafar Hussain Ibupoto. "An Efficient and Functional Fe3O4/Co3O4 Composite for Oxygen Evolution Reaction". Journal of Nanoscience and Nanotechnology 21, nr 4 (1.04.2021): 2675–80. http://dx.doi.org/10.1166/jnn.2021.19098.
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The design of efficient, stable, durable and noble metal free electro catalysts for oxygen evolution reaction (OER) are of immediate need, but very challenging task. In this study, iron induction into cobalt oxide (Co3O4) has resulted composite structure by wet chemical method. The iron impurity has brought an electronic disorder into Fe3O4/cobalt oxide composite thereby efficient oxygen evolution reaction is demonstrated. An addition of iron content into composite resulted the alternation of morphology from Nano rods to clusters of nanoparticles. The successive addition of iron into composite system reduced the onset potential of OER as compared to the pristine cobalt oxide. A Tafel slope of 80 mVdec-1 indicates the favorable oxygen evolution reaction kinetics on the sample 4. An over-potential of 370 mV is required to reach a 10 mAcm-2 current density which is acceptable for a nonprecious catalyst. The catalyst is highly durable and stable for 30 hours. Electrochemical impedance spectroscopy further provided a deeper insight on charge transfer resistance and sample 4 has low charge transfer resistance that supported the OER polarization curves. The sample 4 has more electrochemical active surface area of 393.5 cm2. These obtained results are exciting and highlighting the importance of composite structure and leave a huge space for the future investigations on composite materials for energy related applications.
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Agarwal, Charu, i Levente Csoka. "Functionalization of wood/plant-based natural cellulose fibers with nanomaterials: a review". February 2018 17, nr 02 (1.03.2018): 92–111. http://dx.doi.org/10.32964/tj17.02.92.
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Being the most abundant natural biopolymer on earth, cellulose has been vastly exploited in a range of applications, from writing paper to high-end biosensors. Natural cellulose fibers can be isolated from wood or non-woody plants such as hemp, jute, flax, and bamboo by chemical or mechanical treatments. To make it suitable for targeted applications, cellulose fibers are modified with functional moieties in the nanometer scale. Cellulose has been functionalized with noble metals such as silver and gold nanoparticles for catalysis and antimicrobial applications. A number of metal oxides, such as zinc oxide, titanium dioxide, and tin dioxide have been incorporated into cellulose. The porosity, hydrophilicity, and roughness of cellulose surface makes it an ideal substrate for a plethora of sensing applications. Further, it can be made into a lightweight, portable, foldable, and disposable device, which provides an excellent platform for various point-of-care purposes. Cellulose fibers have also been immobilized with carbon nanomaterials, including carbon nanotubes and graphene oxide. For optical applications, [Fe(hptrz)3](OTs)2 spin-crossover nanoparticles have also been immobilized on cellulose fibers. Likewise, many enzymes, macromolecules, and some polymers have been used to modify natural cellulose for specific end uses. This review focuses on recent developments in the modification or immobilization of functional materials on cellulose fibers, in macro-scale only, obtained from wood or plant sources.
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Tereshchenko, Andrei, Danil Pashkov, Alexander Guda, Sergey Guda, Yury Rusalev i Alexander Soldatov. "Adsorption Sites on Pd Nanoparticles Unraveled by Machine-Learning Potential with Adaptive Sampling". Molecules 27, nr 2 (6.01.2022): 357. http://dx.doi.org/10.3390/molecules27020357.
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Catalytic properties of noble-metal nanoparticles (NPs) are largely determined by their surface morphology. The latter is probed by surface-sensitive spectroscopic techniques in different spectra regions. A fast and precise computational approach enabling the prediction of surface–adsorbate interaction would help the reliable description and interpretation of experimental data. In this work, we applied Machine Learning (ML) algorithms for the task of adsorption-energy approximation for CO on Pd nanoclusters. Due to a high dependency of binding energy from the nature of the adsorbing site and its local coordination, we tested several structural descriptors for the ML algorithm, including mean Pd–C distances, coordination numbers (CN) and generalized coordination numbers (GCN), radial distribution functions (RDF), and angular distribution functions (ADF). To avoid overtraining and to probe the most relevant positions above the metal surface, we utilized the adaptive sampling methodology for guiding the ab initio Density Functional Theory (DFT) calculations. The support vector machines (SVM) and Extra Trees algorithms provided the best approximation quality and mean absolute error in energy prediction up to 0.12 eV. Based on the developed potential, we constructed an energy-surface 3D map for the whole Pd55 nanocluster and extended it to new geometries, Pd79, and Pd85, not implemented in the training sample. The methodology can be easily extended to adsorption energies onto mono- and bimetallic NPs at an affordable computational cost and accuracy.
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Zhang, Mingya, Xue Xiao, Yan Wu, Yue An, Lixin Xu i Chao Wan. "Hydrogen Production from Ammonia Borane over PtNi Alloy Nanoparticles Immobilized on Graphite Carbon Nitride". Catalysts 9, nr 12 (1.12.2019): 1009. http://dx.doi.org/10.3390/catal9121009.
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Graphite carbon nitride (g-C3N4) supported PtNi alloy nanoparticles (NPs) were fabricated via a facile and simple impregnation and chemical reduction method and explored their catalytic performance towards hydrogen evolution from ammonia borane (AB) hydrolysis dehydrogenation. Interestingly, the resultant Pt0.5Ni0.5/g-C3N4 catalyst affords superior performance, including 100% conversion, 100% H2 selectivity, yielding the extraordinary initial total turnover frequency (TOF) of 250.8 molH2 min−1 (molPt)−1 for hydrogen evolution from AB at 10 °C, a relatively low activation energy of 38.09 kJ mol−1, and a remarkable reusability (at least 10 times), which surpass most of the noble metal heterogeneous catalysts. This notably improved activity is attributed to the charge interaction between PtNi NPs and g-C3N4 support. Especially, the nitrogen-containing functional groups on g-C3N4, serving as the anchoring sites for PtNi NPs, may be beneficial for becoming a uniform distribution and decreasing the particle size for the NPs. Our work not only provides a cost-effective route for constructing high-performance catalysts towards the hydrogen evolution of AB but also prompts the utilization of g-C3N4 in energy fields.
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Xu, Zhixiao, i Xiaolei Wang. "Nickel-Molybdenum Carbide/Nitrogen-Doped Carbon Mott-Schottky Nanoarray for Water Spitting". ECS Meeting Abstracts MA2022-01, nr 55 (7.07.2022): 2307. http://dx.doi.org/10.1149/ma2022-01552307mtgabs.
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Electrochemical water splitting, composed of two half reactions: the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER), is under intensive research to the development of H2 fuels to replace fossil fuels. Since both reactions are sluggish, catalysts are usually required to boost them. The state-of-the-art catalysts for both reactions are based on noble metals, such as Pt-based catalysts for HER and Ir or Ru-based catalysts for OER. Unfortunately, the high price and scarcity of these noble metals suppress the widespread application of water splitting. Hence, it is imperative to develop active, durable, low-cost and earth-abundant non-noble-metal electrocatalysts.[1] Among them, molybdenum carbide (Mo2C) has garnered tremendous attention as HER/OER catalysts owing to its Pt-like electronic structure and wide-pH-range catalytic performance. [2] Unfortunately, the catalytic activity of Mo2C towards HER or OER is still inferior to most advanced catalysts. One effective strategy to enhance electrocatalytic performance involves coupling and doping of Mo2C with late transition metals, e.g., Fe, Co, and Ni, which modifies electronic structure and adds active sites, metal-Mo2C interfaces. Unfortunately, similar to Mo2C, metal nanoparticles also tend to aggregate during preparation and operation. A semiconductive carbon catalyst support alleviating aggregation is usually the solution by not only conformally dispersing nanocatalysts but also providing heteroatom dopants and forming metal-semiconductor Mott-Schottky interface for further enhancing catalytic activity.[3] Besides the selection of catalysts with optimized structure and composition at the material level, the structure of electrodes derived from assembled catalysts at the device level also have a crucial influence on the water electrolyzer. Compared with powdery electrocatalysts with relatively large overpotential and easier peeling off from the electrode, self-supported hierarchical nanoarrayed electrodes are more promising for water electrolyzer because these electrodes facilitate transportation of charges and matter and thus reaction kinetics during HER/OER due to binder-free feature, catalysts-substrate seamless contact and highly exposed surface area.[4] We develop here the making of nickel-molybdenum carbide heterostructures embedded in large-area (100 cm2) hierarchically assembled nitrogen-enriched carbon, forming Mott-Schottky array on nickel foam (Ni-Mo2C/NC@NF).[5] The Ni-Mo2C/NC array is directly applied as the bifunctional catalyst with high activity and durability in alkaline electrolyte. Particularly, an extremely low overpotential of 40 mV is needed to generate hydrogen. Density functional theory calculation revealed that the formation of Ni-Mo2C Mott/NC Schottky interfaces enables favorable electronic structures for electrocatalytic water splitting. Besides, 3D hierarchical structure provides exposed active sites, facilitates mass and charge transfer, graphitic shells enhance stability. A symmetric electrolyzer using Ni-Mo2C/NC@NF generates 10 mA cm-2 at 1.59 V and operates steadily for 150 h, which even outperforms the noble metal couple, Pt/C//RuO2 for water electrolysis. The scalability, activity and durability renders Ni-Mo2C/NC@NF potential industrial application. Reference 1. M. Walter, N. Lewis et al, Chem. Rev. 2010, 110, 11, 6446. 2. M. Miao, B. Y. Xia, X. Wang et al, Chem. Eur. J. 2017, 23, 10947. 3. F. Yu, Y. Li et al Nanoscale, 2018,10, 6080. 4. H. Sun, F. Cheng., J. Chen et al. Adv. Mater. 2020, 32, 1806326. 5. Z. Xu, S. Jin, M. H. Seo, X. Wang, Appl. Catal. B: Environ. 2021, 292, 120168
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Weerawardene, K. L. Dimuthu M., i Christine M. Aikens. "Comparison and convergence of optical absorption spectra of noble metal nanoparticles computed using linear-response and real-time time-dependent density functional theories". Computational and Theoretical Chemistry 1146 (grudzień 2018): 27–36. http://dx.doi.org/10.1016/j.comptc.2018.11.005.
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Simonenko, Elizaveta P., Nikolay P. Simonenko, Artem S. Mokrushin, Tatiana L. Simonenko, Philipp Yu Gorobtsov, Ilya A. Nagornov, Ghenadii Korotcenkov, Victor V. Sysoev i Nikolay T. Kuznetsov. "Application of Titanium Carbide MXenes in Chemiresistive Gas Sensors". Nanomaterials 13, nr 5 (24.02.2023): 850. http://dx.doi.org/10.3390/nano13050850.
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The titanium carbide MXenes currently attract an extreme amount of interest from the material science community due to their promising functional properties arising from the two-dimensionality of these layered structures. In particular, the interaction between MXene and gaseous molecules, even at the physisorption level, yields a substantial shift in electrical parameters, which makes it possible to design gas sensors working at RT as a prerequisite to low-powered detection units. Herein, we consider to review such sensors, primarily based on Ti3C2Tx and Ti2CTx crystals as the most studied ones to date, delivering a chemiresistive type of signal. We analyze the ways reported in the literature to modify these 2D nanomaterials for (i) detecting various analyte gases, (ii) improving stability and sensitivity, (iii) reducing response/recovery times, and (iv) advancing a sensitivity to atmospheric humidity. The most powerful approach based on designing hetero-layers of MXenes with other crystals is discussed with regard to employing semiconductor metal oxides and chalcogenides, noble metal nanoparticles, carbon materials (graphene and nanotubes), and polymeric components. The current concepts on the detection mechanisms of MXenes and their hetero-composites are considered, and the background reasons for improving gas-sensing functionality in the hetero-composite when compared with pristine MXenes are classified. We formulate state-of-the-art advances and challenges in the field while proposing some possible solutions, in particular via employing a multisensor array paradigm.
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Cheng, Chunyu, Yiming Zou, Jiahui Li, Amanda Jiamin Ong, Ronn Goei, Jingfeng Huang, Shuzhou Li i Alfred Iing Yoong Tok. "Adsorption and Reaction Mechanisms of Direct Palladium Synthesis by ALD Using Pd(hfac)2 and Ozone on Si (100) Surface". Processes 9, nr 12 (13.12.2021): 2246. http://dx.doi.org/10.3390/pr9122246.
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Palladium nanoparticles made by atomic layer deposition (ALD) normally involve formaldehyde or H2 as a reducing agent. Since formaldehyde is toxic and H2 is explosive, it is advantageous to remove this reducing step during the fabrication of palladium metal by ALD. In this work we have successfully used Pd(hfac)2 and ozone directly to prepare palladium nanoparticles, without the use of reducing or annealing agents. Density functional theory (DFT) was employed to explore the reaction mechanisms of palladium metal formation in this process. DFT results show that Pd(hfac)2 dissociatively chemisorbed to form Pd(hfac)* and hfac* on the Si (100) surface. Subsequently, an O atom of the ozone could cleave the C–C bond of Pd(hfac)* to form Pd* with a low activation barrier of 0.46 eV. An O atom of the ozone could also be inserted into the hfac* to form Pd(hfac-O)* with a lower activation barrier of 0.29 eV. With more ozone, the C–C bond of Pd(hfac-O)* could be broken to produce Pd* with an activation barrier of 0.42 eV. The ozone could also chemisorb on the Pd atom of Pd(hfac-O)* to form O3-Pd(hfac-O)*, which could separate into O-Pd(hfac-O)* with a high activation barrier of 0.83 eV. Besides, the activation barrier was 0.64 eV for Pd* that was directly oxidized to PdOx by ozone. Based on activation barriers from DFT calculations, it was possible to prepare palladium without reducing steps when ALD conditions were carefully controlled, especially the ozone parameters, as shown by our experimental results. The mechanisms of this approach could be used to prepare other noble metals by ALD without reducing/annealing agents.
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Bernasconi, Roberto, Caterina Credi, Marinella Levi i Luca Magagnin. "Self-Activating Metal-Polymer Composites for the Selective Electroless Metallization of 3D Printed Parts". ECS Meeting Abstracts MA2022-02, nr 23 (9.10.2022): 970. http://dx.doi.org/10.1149/ma2022-0223970mtgabs.
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Nowadays, polymer based additive manufacturing (AM) is widely recognized as a powerful technology for the fabrication of complex three-dimensional objects of virtually any shape in a time, material, and cost effective way. Thanks to their characteristic advantages over conventional manufacturing strategies, AM technologies are the subject of relevant research efforts. In particular, great attention is placed on developing novel 3D printable materials characterized by improved properties and, among all, by novel functionalities, such as magnetic [1] and conductive properties [2]. In order to do this, the most common strategy relies on doping polymeric matrices with nanoparticles, obtaining thus functional 3D printable polymeric composites. Metal containing composites, in particular, can be exploited for their magnetic properties or for their mechanical behavior but also for their potential capability to trigger electroless deposition. It is well-known that electroless plating requires the presence of a catalytic surface, which can be constituted by the metallic particles embedded in the 3D printed composite. In this way, the need to activate the surface of non-conductive polymeric 3D printed parts can be avoided [3]. In addition, metallization can be carried out selectively by fabricating parts in a multi-material printing process [4] with both metal loaded and non-loaded materials. Since only the layers that contain the particles can metallize, conductive regions can be alternated with insulating zones to create metallic functional patterns on the surface of printed parts. This approach can enable the 3D printing of selectively self-metallizing parts, with possible applicability in the production of flexible and highly tridimensional electronic circuits, radiofrequency devices, microelectromechanical systems or microfluidic setups. The present work focuses on the development of a stereolithography (SLA) printable composite based on an acrylate resin loaded with nickel microparticles and its application as self-catalytic material for electroless metallization. This approach, unprecedented for SLA resins, eliminates the need of noble metal activation of the surface. Moreover, the usage of Ni is of great interest also due to the other properties that it can potentially impart to the printed parts: improved mechanical properties, high thermal conductivity, magnetizability. The SLA printability of the metal-loaded resin is assessed and the morphological properties of the 3D printed composites are investigated. Subsequently, the functional properties of the composites are determined, placing a particular emphasis on their capability to trigger NiP and Cu electroless deposition. Finally, the possibility to selectively metallize only specific areas is successfully demonstrated by metallizing a Ni-loaded pattern printed on a Ni-free base. [1] Huber et al.; Appl. Phys. Lett. 109, 162401 (2016) [2] Postiglione et al.; Compos. Part A Appl. Sci. Manuf. 76, 110-114 (2015) [3] Bernasconi et al.; J. Electrochem. Soc. 164, B3059–B3066 (2017) [4] Choi et al.; J. Mater. Process. Technol. 211, 318–328 (2011)
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Shaimardan, E., S. K. Kabdrakhmanova, M. M. Beisebekov, B. S. Selenova, Zh Imangazinova i S. Sydykbayeva. "NICKEL NANOCATALYST FOR HYDRODECHLORINATION OF POLYCHLORINATED BIPHENYLS". NNC RK Bulletin, nr 2 (6.07.2023): 74–81. http://dx.doi.org/10.52676/1729-7885-2023-2-74-81.
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Currently, nanomaterials are an important class of materials in the field of synthesis of efficient and selective catalysts with desired properties due to their unique physical and chemical properties. The presence of nanosized particles of transition metals undoubtedly improves the course of the hydrodechlorination of polychlorinated biphenyls (PCBs) and makes it possible to reduce the content of the noble metal in the catalyst. In order to obtain active and stable heterogeneous catalysts for the neutralization of persistent organic pollutants (POPs), the correct choice of carrier and method of catalyst synthesis is required. In this work, the synthesis of a nickel nanocatalyst was carried out using the wet impregnation method for the hydrodechlorination of PCBs. Commercial activated carbon grade BAU-A was pre-modified with hydrochloric acid and used as a carrier (ACm) of the catalyst. Using modern physical and chemical methods, the main properties of the synthesized nanocatalyst were investigated. The IR spectroscopy has established that the carboxyl and carbonyl groups of ACm are the main functional groups that fix nickel in the bulk of the carrier. The nickel nanocatalyst has a developed surface, where nickel nanoparticles are deposited in micro- and mesopores of the carrier. The degree of conversion of 2,2',3,3',4-pentachlorobiphenyl is 84.21%, which indicates the catalytic activity of nickel nanocatalysts with respect to POPs.
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Kawaguchi, Tomoya, Vladimir Komanicky, Vitalii Latyshev, Wonsuk Cha, Evan Maxey, Ross Harder, Tetsu Ichitsubo i Hoydoo You. "Strain Evolution in Pt-Ni Alloy Nanoparticles during Electrochemical Ni Leaching Revealed By Bragg Coherent Diffraction Imaging". ECS Meeting Abstracts MA2022-01, nr 35 (7.07.2022): 1455. http://dx.doi.org/10.1149/ma2022-01351455mtgabs.
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Alloy catalysts such as Pt-M (M: other metal elements) have been extensively developed to improve the sluggish oxygen reduction reaction (ORR) that limits the efficiencies of fuel cells and metal-air batteries. Their catalytic activity is potentially enhanced by strain induced in a nearly pure Pt "shell" formed by dissolving the alloyed metal (M) from the surface. It is, therefore, of great importance to reveal the strain distribution on the Pt shell in situ so that we can exploit this mechanism to design new alloy catalysts. Yet, it has been challenging to analyze the strain on the shell because it inevitably requires a technique that can image the strain field of the nanoparticles with high spatial resolution. In this study,1 we successfully revealed the strain of the exemplary Pt-Ni alloy nanoparticles in detail from the 3D images obtained by using a novel synchrotron technique, “Bragg Coherent X-ray Diffraction Imaging” (BCDI), which can directly image minute atomic displacement field owing to the X-ray coherence. Pt-Ni nanoparticles with compositions of Pt2Ni3 (Ni rich), Pt1Ni1 (moderate Ni), and Pt3Ni2 (Ni poor) were observed by BCDI during cyclic voltammetry cycles, in which the less noble metal Ni electrochemically leached from the alloy. This cycling induced tensile strain inside particles in all the compositions, implying that the formation of a Pt shell on the surface strained the core of the particle because of the lattice mismatch between the Pt-Ni alloys and Pt. The strain in the shell was evaluated from a core-shell elastic model using the parameters obtained in the 3D images. A compressive circumferential strain in the shell was observed in all the compositions, and the Pt1Ni1 particle showed the largest compressive circumferential strain of 5%. Since the compressive strain is reported to facilitate the enhanced ORR,2 the compositional dependence of the strain magnitude observed in this study was in excellent agreement with the previous study performed with nm-size particles where Pt1Ni1 exhibits the highest activity among a wide range of compositions.3 A similar strain-activity relation was also inferred in a powder X-ray diffraction studies of core-shell Pt x Co1-x alloys,4 suggesting it is a widely applicable phenomenon. The present study demonstrated that the strain on alloy nanoparticles can be quantitatively determined by BCDI during electrochemical reactions, which enables us to exploit surface strain in designing a wide range of electrocatalysts. T. Kawaguchi et al., Nano Letters, 21, 5945–5951 (2021). H. Wang et al., Science, 354, 1031–1036 (2016). C. Wang et al., Advanced Functional Materials, 21, 147–152 (2011). D. Wang et al., Nature Materials, 12, 81–87 (2013).
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Harn, Yeu-Wei, Shuang Liang, Shuanglong Liu, Yan Yan, Zewei Wang, Jun Jiang, Jiawei Zhang i in. "Tailoring electrocatalytic activity of in situ crafted perovskite oxide nanocrystals via size and dopant control". Proceedings of the National Academy of Sciences 118, nr 25 (14.06.2021): e2014086118. http://dx.doi.org/10.1073/pnas.2014086118.
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Perovskite oxides (ABO3) have been widely recognized as a class of promising noble-metal–free electrocatalysts due to their unique compositional flexibility and structural stability. Surprisingly, investigation into their size-dependent electrocatalytic properties, in particular barium titanate (BaTiO3), has been comparatively few and limited in scope. Herein, we report the scrutiny of size- and dopant-dependent oxygen reduction reaction (ORR) activities of an array of judiciously designed pristine BaTiO3 and doped BaTiO3 (i.e., La- and Co-doped) nanoparticles (NPs). Specifically, a robust nanoreactor strategy, based on amphiphilic star-like diblock copolymers, is employed to synthesize a set of hydrophobic polymer-ligated uniform BaTiO3 NPs of different sizes (≤20 nm) and controlled compositions. Quite intriguingly, the ORR activities are found to progressively decrease with the increasing size of BaTiO3 NPs. Notably, La- and Co-doped BaTiO3 NPs display markedly improved ORR performance over the pristine counterpart. This can be attributed to the reduced limiting barrier imposed by the formation of -OOH species during ORR due to enhanced adsorption energy of intermediates and the possibly increased conductivity as a result of change in the electronic states as revealed by our density functional theory–based first-principles calculations. Going beyond BaTiO3 NPs, a variety of other ABO3 NPs with tunable sizes and compositions may be readily accessible by exploiting our amphiphilic star-like diblock copolymer nanoreactor strategy. They could in turn provide a unique platform for both fundamental and practical studies on a suite of physical properties (dielectric, piezoelectric, electrostrictive, catalytic, etc.) contingent upon their dimensions and compositions.
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Dimitrov, Nikolay. "(Electrodeposition Division Research Award) Impact of Electrodeposition on the Design and Synthesis of Nanoporous Functional Materials". ECS Meeting Abstracts MA2022-02, nr 24 (9.10.2022): 1006. http://dx.doi.org/10.1149/ma2022-02241006mtgabs.
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The sustainable growth of efficient and durable functional nanomaterials applicable in a variety of practical fields is founded on the creative design, rational synthesis, extensive characterization, and realistic testing of products developed by countless hard-working research teams. Many of these nanomaterials must include high-cost and scarcely distributed elements and compounds that need to be either eliminated or minimally used as much as it is possible. Most commonly, such minimization has been approached by synthesizing the materials of interest in the form of nanoparticles. Nanoparticles are undoubtedly superior to other type of materials in a variety of fields and applications because of their large surface area to volume ratio and unique chemical and physical properties. Their implementation in practice also addresses well the objective for minimization of the use of expensive elements and compounds. At the same time, as class of nanomaterilas, the nanopartiles suffer some drawbacks like loss of material during synthesis, surface contamination/blockage by chemicals used in their synthesis, mechanical disconnection from carrier electrodes, and / or aggregation during exploitation. Such unwelcome developments often make it difficult to keep the cost low and/or lead to a reduction of the active surface area and thus, to loss of functionality, performance, and stability. A way of addressing some of the mentioned shortcomings is to employ electrochemical approaches for synthesizing alternative nanostructured materials directly on the carrier electrode. Such approach not only provides for better adhesion and contamination free surface, but also enables an efficient control of the amount of the deposited material along with flexibility in the structuring during the material synthesis, thus most-certainly reducing its overall cost of the final product. The electrochemical means inevitably include controlled electrodeposition of a binary / ternary alloy layer with a desired thickness and pre-selected elemental composition. A naturally following step in the material's synthesis is the selective oxidative dissolution of the less / least noble metal (a.k.a. de-alloying) to create a continuous nanoporous film with tunable pore and ligament size comprising a length-scale in the single-digit nanometer range. Finally, as-synthesized nanostructured films may either be employed directly for the purposes of the intended applications or be subjected to an additional surface functionalization by a further electrodeposition or electroless of a thin layer with specific properties that is aimed at boosting the material's functionality, performance and stability. This talk will introduce the use of electrochemical means in the design and synthesis of continuous nanoporous Au- and Cu-based functional alloy nanomaterials with applications in electrocatalysis, environmental protection, and electronic packaging. The discussed synthetic approaches will include bulk alloy electrodeposition, electrochemical de-alloying, and electrochemical atomic layer deposition for surface functionalization by films with a thickness in the range from a sub-monolayer to a few monolayers. The presentation of each class of nanostructured materials of interest to this talk will include a conceptual description of their synthetic routines, followed by an electrochemical and ultra-high vacuum-based characterization results, and concluded with a glimpse into the outcome of standard performance tests of the functionality, performance, and stability of said materials in intended applications. Finally, aspects of the materials performance associated with hypothesized mechanistic views will be critically discussed in comparison with other nanoparticulate and/or nanostructured counterpart materials in the literature.
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Chandra, Manabendra, i Puspendu K. Das. "Green Routes to Noble Metal Nanoparticle Synthesis". International Journal of Green Nanotechnology: Physics and Chemistry 1, nr 1 (11.08.2009): P10—P25. http://dx.doi.org/10.1080/19430870902909767.
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Roca, Maryuri, i Amanda J. Haes. "Probing cells with noble metal nanoparticle aggregates". Nanomedicine 3, nr 4 (sierpień 2008): 555–65. http://dx.doi.org/10.2217/17435889.3.4.555.
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Ah, Chil Seong, Hyouk Soo Han, Kwan Kim i Du-Jeon Jang. "Phototransformation of Alkanethiol-derivatized Noble Metal Nanoparticle". Pure and Applied Chemistry 72, nr 1-2 (1.01.2000): 91–99. http://dx.doi.org/10.1351/pac200072010091.
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Photon-initiated shape transformation of n-alkanethiol-derivatized noble metal nanoparticles has been studied with variations of metal, alkanethiol, and solvent. Silver nanoparticles undergo fragmentation upon irradiation while gold ones barely do. Silver/gold composite particles follow the case of silver with a reduced efficiency. The efficiency decreases as alkanethiol length or solvent dipole moment increases. Following the conduction of thermalized photon energy, alkanethiol can dissociate in a period of heat dissipation, and some of dethiolated particles fragment within the recombination time. Prior to the thermal conduction, shape transformation via melt and vaporization also occurs for both metals but this effect is less apparent for silver because of more notable fragmentation followed. The difference in the transformation of two metals is ascribed to the differences in work function, oxidation potential, atomization enthalpy, and particle size. Smaller fragmentation efficiency with more polar solvent or longer alkanethiol is attributed mainly to relatively smaller dissociation rate compared with heat dissipation rate.
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Hayashi, Yamato, Masahiro Inoue, Ichitito Narita, Katsuaki Suganuma i Hirotsugu Takizawa. "Eco-Fabrication of Metal Nanoparticle Related Materials by Home Electric Appliances". Materials Science Forum 620-622 (kwiecień 2009): 185–88. http://dx.doi.org/10.4028/www.scientific.net/msf.620-622.185.
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Applications of various noble metal nanoparticles were investigated for newly, ecology and economy home electric appliances (microwave, ultrasonic) used system. Noble metal oxides have merit in metal particles fabrication, as one of these example example, there are decomposed by only heating in air. That is, noble metal oxide don't use strong reduction atmosphere. This reduction is ecologically clean, because many noble metal oxides are not toxic and during decomposition O2 is evolved. We have reduced noble metal oxides by microwave and ultrasound, and tried to fabricate noble metal nanoparticles, and investigated various processing. These energy are widely used by home electric appliances. By choosing suitable process and conditions, it is reasonable to expect that home electric appliances ecology and economy fabrications can be extended to obtain simply various noble metal nanoparticles related materials.
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Cao, Peng-Fei, Yun-Hui Yan, Joey Dacula Mangadlao, Li-Han Rong i Rigoberto Advincula. "Star-like copolymer stabilized noble-metal nanoparticle powders". Nanoscale 8, nr 14 (2016): 7435–42. http://dx.doi.org/10.1039/c5nr07000g.
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Muskens, Otto, Dimitris Christofilos, Natalia Del Fatti i Fabrice Vallée. "Optical response of a single noble metal nanoparticle". Journal of Optics A: Pure and Applied Optics 8, nr 4 (27.03.2006): S264—S272. http://dx.doi.org/10.1088/1464-4258/8/4/s28.
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