Download or read book Synthesis of Platinum and Platinum copper Branches Nanoparticles for Electrooxidation of Methanol written by Eric Courtland Taylor and published by . This book was released on 2013 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: Platinum and Pt alloys are among the most important heterogeneous catalysts for many organic reactions and electrochemical reactions associated with the fuel cell technologies. How to reduce Pt usage while maintaining the performance of the catalysts becomes a subject for intensive research in materials chemistry. For heterogeneous catalysis, the catalytic reactivity and selectivity are strongly correlated with different crystallographic facets exposed on the surface. The facets with high-index planes whose Miller indices with at one is larger than unity are generally more active than those with low-index planes (e.g., {100}, {111}, and {110}). Tuning the morphology of the nanoparticles to expose more high-index planes on the surface can improve the catalytic activity of the nanoparticles. As compared to isotropic nanoparticles, the branched nanostructures are the promising morphology that can improve both the activity and stability of the catalysts. In this work, a two-step polyol synthesis has been developed to synthesize the branched nanostructures of Pt at high-yield. This two-step process involves a slow reduction using ethylene glycol in the presence of oxidative etchants, following by a fast reduction using ascorbic acid. The slow reduction kinetics facilitates the formation of cubooctahedral single-crystal seeds while the fast reduction kinetics allows for the overgrowth of nanocrystals along the {111} facets in a short period of time, resulting in the branched nanostructures. By co-reducing Pt and Cu precursors, this approach has been demonstrated to synthesize the Pt-Cu dendritic nanostructures for the first time. The catalytic activity of these Pt and Pt-Cu nanostructures has been studied for MOR. It was found that Pt branched nanostructures reduced the CO-poisoning as compared to the Pt/C and the dendritic Pt-Cu nanostructures showed both enhanced resistance of CO-poisoning and improved efficiency of ethanol oxidation.
Download or read book Platinum ruthenium Nanotubes and Platinum ruthenium Coated Copper Nanowires as Efficient Catalysts for Electro oxidation of Methanol written by and published by . This book was released on 2015 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: The sluggish kinetics of methanol oxidation reaction (MOR) is a major barrier to the commercialization of direct methanol fuel cells (DMFCs). In this study, we report a facile synthesis of platinum-ruthenium nanotubes (PtRuNTs) and platinum-ruthenium-coated copper nanowires (PtRu/CuNWs) by galvanic displacement reaction using copper nanowires as a template. The PtRu compositional effect on MOR is investigated; the optimum Pt/Ru bulk atomic ratio is about 4 and surface atomic ratio about 1 for both PtRuNTs and PtRu/CuNWs. Enhanced specific MOR activities are observed on both PtRuNTs and PtRu/CuNWs compared with the benchmark commercial carbon-supported PtRu catalyst (PtRu/C, Hispec 12100). Finally, x-ray photoelectron spectroscopy (XPS) reveals a larger extent of electron transfer from Ru to Pt on PtRu/CuNWs, which may lead to a modification of the d-band center of Pt and consequently a weaker bonding of CO (the poisoning intermediate) on Pt and a higher MOR activity on PtRu/CuNWs.
Download or read book Voltammetric and NMR Studies of the Electrochemical Oxidation of Methanol on Platinum Nanoparticles written by Patrick Brian McGrath and published by . This book was released on 2007 with total page 272 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Platinum Monolayer Electrocatalysts written by Radoslav Adzic and published by Springer Nature. This book was released on 2020-08-11 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes a science and technology of a new type of electrocatalysts consisting of a single atomic layer of platinum on suitable supports. This development helped overcome three major obstacles—catalysts‘ cost, activity, and stability—for a broad range of fuel cell applications. The volume begins with a short introduction to the science of electrocatalysis, covering four reactions important for energy conversion in fuel cells. A description follows of the properties of metal monolayers on electrode surfaces, and underpotential deposition of metals. The authors then describe the concept of Pt monolayer electrocatalysts and its implications and their synthesis by galvanic displacement of less-noble metal monolayers and other methods. The main part of the book presents a discussion of catalysts’ characterization and catalytic properties of Pt monolayers for the four main reactions of electrochemical energy conversion: oxygen reduction and oxidation of hydrogen, methanol and ethanol. The book concludes with a treatment of scale-up syntheses, fuel cell tests, catalysts’ stability and application prospects.
Download or read book Preparation of Nanoparticles of Platinum Nickel and Copper and Studies of Film Formation Oxidation and Carburization written by Jie Ren and published by . This book was released on 2021 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: In a separate study, different composition of nanoparticles of CuxNiy (Cu, Cu1Ni1, Cu1Ni2, Cu1Ni3, Cu2Ni1 and Ni) with a core/shell structure were synthesized by two reducing agents: sodium hypophosphite (NaH2PO2) and hydrazine (N2H4), via reduction of copper acetate tetrahydrate and nickel acetate tetrahydrate, respectively, in ethylene glycol. NaH2PO2 reduced Cu2+ at 100 °C and reduced Ni2+ at 175 °C, while N2H4 with NaOH, which have a higher reducing power, can reduce Cu2+ at room temperature and reduce Ni2+ at 100 °C. Both of these two processes form Cu/Ni core/shell structures. The Cu/Ni core/shell nanoparticles were successfully assembled into uniform films and this set of core/shell structure can be used as Cu/Ni diffusion couple.
Download or read book Synthesis and Characterization of Platinum based Multi component Catalysts for Direct Methanol Fuel Cells written by Li Ren and published by . This book was released on 2007 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt: "In the thesis work, Pt-based binary, ternary, quaternary alloy anode catalysts supported on sonochemically treated multi-walled carbon nanotubes (CNTs) were synthesized with ethylene glycol reduction of corresponding metal chloride salts. Inductively coupled plasma-mass spectroscopy (ICP-MS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) were used for catalyst characterization. Cyclic voltammetry for methanol oxidation and CO stripping were used to evaluate the performance of the catalysts. PtRu nanoparticles supported on CNTs (PtRu/CNT) were prepared under a series of pHs. It was found that the PtRu particle size, composition, and catalytic activity were all sensitive to the deposition pHs. CO stripping results provided the peak potential and active surface area for each catalyst. The atomic ratios tended to approach the predetermined ratio 1:1 with the increase of pH, which is favored by bi-functional catalytic mechanism. PtRu catalysts prepared at higher pHs presented better electrochemical activity toward methanol oxidation. Humidified oxygen treatment of the PtRu/CNT led to improved activity of the catalysts toward methanol electro-oxidation, implying that Ru hydroxide is better than Ru as a co-catalyst. PtRu, PtOs, PtRuOs, and PtRuOsIr nanoparticles supported on CNTs with atomic ratios of Pt:Ru (tr:46), Pt:Os (80:20), Pt:Ru:Os (54:36:10), and Pt:Ru:Os:Ir (44:36:10:5) were prepared. Cyclic voltammetry for the methanol oxidation and CO stripping at the catalysts showed that PtRu/CNT and PtRuOsIr/CNT have the best performance toward methanol oxidation, PtRuOs/CNT has the lowest activity, but PtOs/CNT exhibits better catalytic activity only at potential or 0.73 V"--Abstract, leaf iii.
Download or read book Synthesis and Characterisation of Platinum based Electrocatalysts and Electrocatalytic Activity Towards Methanol Electro oxidation written by and published by . This book was released on with total page 1 pages. Available in PDF, EPUB and Kindle. Book excerpt: Methanol electrochemical oxidation reaction (MOR) catalysts are receiving great interest especially for the application in direct methanol fuel cells (DMFCs). Much interest in DMFCs development is focused on portable power applications, because DMFCs can be better miniaturised than other fuel cells. [partial abstract].
Download or read book Electrochemical Investigation of Platinum Nanoparticles Supported on Carbon Nanotubes as Cathode for Direct Methanol Fuel Cell written by Asanda Ntlauzana and published by . This book was released on 2010 with total page 236 pages. Available in PDF, EPUB and Kindle. Book excerpt: The particles of the Pt metal were well dispersed on carbon nanotubes when EG was used and in isopropanol poor dispersion was observed and no further investigation was done on them. The platinum wt% on the supports observed from EDS was 21.8, 19.10 and 16.74wt% for Pt/EMWCNT, Pt/LPGCNT and Pt/ commercial CNT respectively. Pt/LPGMWCNT showed high electro-catalytic activity of 2.48 mA and active surface area of 76 m2/g, toward oxygen reduction, observed from cyclic voltammogram in iv sulfuric acid. Pt/LPGMWCNT also showed better tolerance toward methanol, however it was not highly active towards methanol, and hence the methanol oxidation peak current observed between 0.75 and 08 potential was the smallest. In this study a wide range of instruments was used to characterize the properties and behavior of Platinum nanoparticles on multi-wall carbon nanotubes. To add to the already mentioned, Scanning electrochemical microscopy (SEM), proton induced x-ray emission (PIXE), scanning electrochemical microscopy (SECM) and Brunauer-Emmett Tellar (BET) were also used.
Download or read book Investigation of Synthesis Methods for Improved Platinum Ruthenium Nanoparticles Supported on Multi Walled Carbon Nanotube Electrocatalysts for Direct Methanol Fuel Cells written by Lindiwe Eudora Khotseng and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book chapter reports on various catalyst synthesis methods (impregnation, polyol, modified polyol, and microwave-assisted modified polyol methods) to determine which method would result in the most electrochemically active platinum-ruthenium (PtRu) electrocatalyst supported on multi-walled carbon nanotubes (MWCNTs) for methanol oxidation reaction in an acidic medium. Different techniques were used to characterize the synthesized catalysts, including the high-resolution transmission electron microscope used for morphology and calculating particle sizes, and X-ray diffraction for determining crystalline sizes. The electroactive catalyst surface area, ECSA of the electrocatalysts was determined using cyclic voltammetry (CV), while the electroactivity, electron kinetics, and stability of the electrocatalysts towards methanol oxidation were evaluated using CV, electrochemical impedance spectroscopy, and chronoamperometry, respectively. The microwave-assisted modified polyol method produced the PtRu/MWCNT electrocatalyst with the most enhanced electrocatalytic activity compared to other PtRu/MWCNT catalysts produced by the impregnation, polyol, and modified polyol methods.
Download or read book Electrochemical Studies of Methanol Oxidation Reactions at Platinum and Platinum ruthenium Nanoparticle Catalysts in Direct Methanol Fuel Cells written by Zachary Eason and published by . This book was released on 2019 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: "This project aims to investigate an efficient and economic platinum-based catalyst system in DMFCs. The research focused on studying the reactivity of four nanoparticle catalysts on a gold electrode towards methanol oxidation reactions." -- Abstract
Download or read book Platinum Nickel Nanowires as Methanol Oxidation Electrocatalysts written by and published by . This book was released on 2015 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: We investigated platinum(Pt) nickel (Ni) nanowires (PtNiNWs) as methanol oxidation reaction (MOR) catalysts in rotating disk electrode (RDE) half-cells under acidic conditions. Pt-ruthenium (Ru) nanoparticles have long been the state of the art MOR catalyst for direct methanol fuel cells (DMFCs) where Ru provides oxophilic sites, lowering the potential for carbon monoxide oxidation and the MOR onset. Ru, however, is a precious metal that has long term durability concerns. Ni/Ni oxide species offer a potential to replace Ru in MOR electrocatalysis. PtNiNWs were investigated for MOR and oxygen annealing was investigated as a route to improve catalyst performance (mass activity 65% greater) and stability to potential cycling. Our results presented show that PtNiNWs offer significant promise in the area, but also result in Ni ion leaching that is a concern requiring further evaluation in fuel cells.
Download or read book Synthesis Structure and Catalytic Properties of Size selected Platinum Nanoparticles written by Simon Armando Mostafa Covone and published by . This book was released on 2010 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: The use of heterogeneous catalysis is well established in chemical synthesis, energy, and environmental engineering applications. Supported Pt nanoparticles have been widely reported to act as catalysts in a vast number of chemical reactions. In this report, the performance of Pt/ZrO2 nanocatalyst for the decomposition of methanol, ethanol, 2-propanol, and 2-butanol is investigated. The potential of each alcohol for the production of H2 and other relevant products in the presence of a catalyst is studied. All the alcohols studied show some decomposition activity below 200°C which increased with increasing temperature. In all cases, high selectivity towards H2 formation is observed. With the exception of methanol, all alcohol conversion reactions lead to catalyst deactivation at high temperatures (T [greater than]250°C for 2-propanol and 2-butanol, T [greater than]325°C for ethanol) due to carbon poisoning. However, long-term catalyst deactivation can be avoided by optimizing reaction conditions such as operating temperature. In addition, the performance of Pt/[gamma]-Al2O3 is evaluated in the oxidation of 2-propanol. Pt nanoclusters of similar size (~1 nm diameter) but different structure (shape) were found to display distinctively different catalytic properties. All the systems studied achieve high conversion (~ 90%) below 100°C. However, flatter particles display a lower reaction onset temperature, demonstrating superior catalytic performance. Acetone, CO2, and water are generated as products indicating that both partial and complete oxidation are taking place. A number of techniques including AFM, XPS, TEM, HAADF-TEM, XAFS as well as packed-bed reactor experiments were used for sample characterization and evaluation of catalytic performance.
Download or read book Fuel Cell Catalysis written by Andrzej Wieckowski and published by John Wiley & Sons. This book was released on 2009-04-01 with total page 722 pages. Available in PDF, EPUB and Kindle. Book excerpt: Wiley Series on Electrocatalysis and Electrochemistry Fuel Cell Catalysis A Surface Science Approach A Core reference on fuel cell catalysis Fuel cells represent an important alternative energy source and a very active area of research. Fuel Cell Catalysis brings together world leaders in this field, providing a unique combination of state-of-the-art theory and computational and experimental methods. With an emphasis on understanding fuel cell catalysis at the molecular level, this text covers fundamental principles, future challenges, and important current research themes. Fuel Cell Catalysis: Provides a molecular-level description of catalysis for low-temperature polymer-electrolyte membrane fuel cells, including both hydrogen-oxygen cells and direct alcohol cells Examines catalysis issues of both anode and cathode such as oxygen reduction, alcohol oxidation, and CO tolerance Features a timely and forward-looking approach through emphasis on novel aspects such as computation and bio-inspiration Reviews the use and potential of surface-sensitive techniques like vibrational spectroscopy (IR, Raman, nonlinear spectroscopy, laser), scanning tunneling microscopy, X-ray scattering, NMR, electrochemical techniques, and more Reviews the use and potential of such modern computational techniques as DFT, ab initio MD, kinetic Monte Carlo simulations, and more Surveys important trends in reactivity and structure sensitivity, nanoparticles, "dynamic" catalysis, electrocatalysis vs. gas-phase catalysis, new experimental techniques, and nontraditional catalysts This cutting-edge collection offers a core reference for electrochemists, electrocatalysis researchers, surface and physical chemists, chemical and automotive engineers, and researchers in academia, research institutes, and industry.
Download or read book Electrochemical Biosensors written by Serge Cosnier and published by CRC Press. This book was released on 2015-01-26 with total page 405 pages. Available in PDF, EPUB and Kindle. Book excerpt: Since four decades, rapid detection and monitoring in clinical and food diagnostics and in environmental and biodefense have paved the way for the elaboration of electrochemical biosensors. Thanks to their adaptability, ease of use in relatively complex samples, and their portability, electrochemical biosensors now are one of the mainstays of analy
Download or read book Nanocatalysis written by Vivek Polshettiwar and published by John Wiley & Sons. This book was released on 2013-09-30 with total page 755 pages. Available in PDF, EPUB and Kindle. Book excerpt: Exhibiting both homogeneous and heterogeneous catalytic properties, nanocatalysts allow for rapid and selective chemical transformations, with the benefits of excellent product yield and ease of catalyst separation and recovery. This book reviews the catalytic performance and the synthesis and characterization of nanocatalysts, examining the current state of the art and pointing the way towards new avenues of research. Moreover, the authors discuss new and emerging applications of nanocatalysts and nanocatalysis, from pharmaceuticals to fine chemicals to renewable energy to biotransformations. Nanocatalysis features contributions from leading research groups around the world. These contributions reflect a thorough review of the current literature as well as the authors’ first-hand experience designing and synthesizing nanocatalysts and developing new applications for them. The book’s nineteen chapters offer a broad perspective, covering: Nanocatalysis for carbon-carbon and carbon-heteroatom coupling reactions Nanocatalysis for various organic transformations in fine chemical synthesis Nanocatalysis for oxidation, hydrogenation, and other related reactions Nanomaterial-based photocatalysis and biocatalysis Nanocatalysts to produce non-conventional energy such as hydrogen and biofuels Nanocatalysts and nano-biocatalysts in the chemical industry Readers will also learn about the latest spectroscopic and microscopy tools used in advanced characterization methods that shed new light on nanocatalysts and nanocatalysis. Moreover, the authors offer expert advice to help readers develop strategies to improve catalytic performance. Summarizing and reviewing all the most important advances in nanocatalysis over the last two decades, this book explains the many advantages of nanocatalysts over conventional homogeneous and heterogeneous catalysts, providing the information and guidance needed for designing green, sustainable catalytic processes.
Download or read book Handbook of Nanoelectrochemistry written by Mahmood Aliofkhazraei and published by Springer. This book was released on 2015-11-03 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This edited book is devoted to different electrochemical aspects of nano materials. This comprehensive reference text is basically divided in 3 parts: electrochemical synthesis routes for nanosized materials, electrochemical properties of nano materials and electrochemical characterization methods for nanostructures. The Handbook is a reference work to chemists and materials scientists interested in the nano aspects of electrochemistry. The chapters are written by a number of international experts in the field and the content will assist members of both electrochemical and materials communities to keep abreast of developments in the field.
Download or read book Novel Nanomaterials written by George Kyzas and published by BoD – Books on Demand. This book was released on 2018-04-18 with total page 372 pages. Available in PDF, EPUB and Kindle. Book excerpt: "Nanomaterials" is a special topic of recent research and is a milestone of nanoscience and nanotechnology. Nanoscale materials are a series of substances/compounds, in which at least one dimension has smaller size than 100 nm. Nanomaterials have a broad area of development, which is growing rapidly day by day. Their impact on commercial applications as well as on the respective academia and education is huge. The basic points of this book can be divided into synthesis of nanomaterials and their applications. For example, special mention is about metal-oxide nanostructures, nanocomposites, and polymeric nanomaterials. Also, synthesis, characterizations, various processes, fabrications and some promising applications are also developed and analyzed.
