Download or read book Electrochemical Studies and In Situ Electrochemical Nuclear Magnetic Resonance Investigations on Platinum based Bimetallic Electrocatalysts for Direct Methanol Fuel Cells written by Bingchen Du and published by . This book was released on 2009 with total page 392 pages. Available in PDF, EPUB and Kindle. Book excerpt: Two parallel objectives of this thesis research are 1) to investigate the electrocatalytic activities of Pt-based bimetallic nanoparticles (NPs) towards methanol (MeOH) electro-oxidation reaction (MOR), carbon monoxide (CO) tolerance and oxygen reduction reaction (ORR); and 2) to use electrochemical nuclear magnetic resonance (EC-NMR) techniques to investigate the electronic properties of the Pt-based bimetallic electrocatalysts.
Download or read book Synthesis Activation and Electrochemical Study of PT and PT based Bimetallic Nano Particles for Anode Catalysts of Direct Methanol Fuel Cells DMFCs written by Zhufang Liu and published by . This book was released on 2007 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book In situ Spectroscopic Studies of Adsorption at the Electrode and Electrocatalysis written by Shi-Gang Sun and published by Elsevier. This book was released on 2011-08-11 with total page 559 pages. Available in PDF, EPUB and Kindle. Book excerpt: In-Situ Spectroscopic Studies of Adsorption at the Electrode and Electrocatalysis is a new reference on in-situ spectroscopic techniques/applications, fundamentals of electrocatalysis at molecule level, and progresses within electrochemical surface science. Presenting both essential background knowledge at graduate level and original research within the fields of spectroscopy, electrochemistry, and surface science. Featuring 15 chapters by prominent worldwide scholars, based on their recent progress in different aspects of in-situ spectroscopy studies, this book will appeal to a wide audience of scientists. In summary this book is highly suitable for graduates learning basic concepts and advanced applications of in-situ spectroscopy, electrocatalysis and electrode adsorptions. * Written by the most active scientists in the fields of spectroscopy, electrochemistry and surface science* Essential background knowledge for graduate students* A modern reference of cutting-edge scientific research
Download or read book Electrocatalysis of Direct Methanol Fuel Cells written by Jiujun Zhang and published by John Wiley & Sons. This book was released on 2009-10-26 with total page 605 pages. Available in PDF, EPUB and Kindle. Book excerpt: This first book to focus on a comprehensive description on DMFC electrocatalysis draws a clear picture of the current status of DMFC technology, especially the advances, challenges and perspectives in the field. Leading researchers from universities, government laboratories and fuel cell industries in North America, Europe and Asia share their knowledge and information on recent advances in the fundamental theories, experimental methodologies and research achievements. In order to help readers better understand the science and technology of the subject, some important and representative figures, tables, photos, and comprehensive lists of reference papers are also included, such that all the information needed on this topic may be easily located. An indispensable source for physical, catalytic, electro- and solid state chemists, as well as materials scientists and chemists in industry.
Download or read book Structure Dependent Electrochemical Behavior of Carbon Based Electrocatalysts for Applications in Direct Methanol Fuel Cells written by Praveen Kolla and published by . This book was released on 2014 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt: A fuel cell is an electrochemical energy conversion device that efficiently converts chemical energy of fuel into electricity. Among the fuel cells that operate at low-temperatures [(≤ 80oC)], the Direct Methanol Fuel Cell (DMFC) holds a key role in the development of sustainable energy technologies by electrochemical energy conversion of renewable fuel (methanol), without contributing to greenhouse gas emissions. In addition, the high energy-density of methanol makes DMFC a potential candidate to replace rechargeable batteries in electronic devices and automotive power sources. However, expensive platinum-based state-of-the-art catalysts such as PtRu/C and Pt/C have been used to tackle a large number of intermediates regarding Methanol Oxidation Reaction (MOR) at the anode, and slow rate kinetics associated with Oxygen Reduction Reaction (ORR) at the cathode, respectively. In addition, mixed currents caused by methanol cross-over from anode to cathode through Proton Exchange Membrane (PEM) contribute to voltage losses in DMFC. In order to make the DMFC commercially viable, recent research efforts have focused on developing less expensive catalysts by replacing/promoting platinum based catalysts with metal/metal oxide nanostructures, without compromising their electrochemical performance.
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 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 Nano electrocatalyst for Oxygen Reduction Reaction written by Omar Solorza Feria and published by CRC Press. This book was released on 2024-06-21 with total page 350 pages. Available in PDF, EPUB and Kindle. Book excerpt: Global warming switches our reliance from fossil fuels to green, sustainable renewable energy sources. Because of its promising nature, high-efficiency nano-electrocatalysts have sparked interest in renewable energy. Hydrogen fuel cell/polymer electrolyte membrane (PEM) vehicles are the most environmentally conscious electromobility vehicles, with a high energy density and quick refuelling technology, prompting the auto industry to launch a variety of PEM fuel cell vehicles around the world. Oxygen reduction reaction (ORR) primary research interests include fuel cells and metal-air batteries. The sluggish kinetic reaction of ORR, which is responsible for the rate-limiting reaction at the PEM fuel cell cathodic system, further decreases energy efficiency. Optimising ORR for market expansion with cost-effective and efficient nano-electrocatalysts, on the other hand, remains a challenge. The book covers fundamental ORR reaction kinetics theories, tools, and techniques. It also explains the nano electrocatalysts for ORR made of noble, non-noble, and nanocarbon materials. Finally, the book explores the applications of PEM fuel cells and metal-air batteries.
Download or read book In situ Investigation and Mitigation of Carbon Support Corrosion of Cathode Catalyst in PEM Fuel Cells written by Wei Li and published by . This book was released on 2010 with total page 188 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon support corrosion (CSC) is one of the key factors causing cathode electrocatalyst (Pt/C) degradation in proton exchange membrane fuel cells (PEMFC). It is electrochemical oxidation and thus needs to be investigated in-situ with potential imposed. CSC was characterized in-situ and correlated to the Pt redox reactions and Pt-catalyzed oxygen reduction reaction (ORR) by the differential electrochemical mass spectrometry (DEMS) spectra of cathode exhaust gases, CO2, H2 and O2, from a PEMFC fed with humidified H2 and He to the anode and cathode respectively. Furthermore, the catalytic effects on CSC from different oxidation states of Pt were indicated. To determine the oxygen sources and pathways of CSC, oxygen was isotopically labeled by replacing regular water with oxygen-18 (18O) enriched water (H218O, 98%) in DEMS, denoted as 18O-DEMS. 18O-DEMS spectra of the cathode exhaust gases O2, O18O, 18O2, CO2, CO18O and C18O2 during cyclic voltammetry and chronoamperometry were analyzed to verify that water is the main direct oxygen source for CSC. Moreover, water reacts with carbon to produce at least three types of carbon surface oxides, which are further electrochemically oxidized with water to produce CO2 in different potential ranges. After accelerated testing of cathode catalyst degradation in PEMFC using potential cycling between 100-1400 mV at the rate of 400 mV/s, the changes of mass spectra of CO2, H2 and O2 over time showed that the CSC decreases as Pt electrochemically active surface area (ECSA) decreases, i.e. catalyst activity decreases, but the membrane does not degrade significantly in gas permeability. A hypothesis is proposed here that Au nanoparticles (NPs) added to a carbon-supported Pt (Pt/C) catalyst can mitigate the Pt catalytic effects on CSC by suppressing the Pt oxidation. Several methods were tried to synthesize Pt/C (20 wt% Pt) and bimetallic AuPt/C (20 wt% Pt, 5 wt% Au) catalysts including deposition-precipitation, two phase liquid-liquid colloidal, polyol, microwave-assisted polyol, and surface redox methods. TEM pictures showed that the EG method (polyol method using ethylene glycol), microwave-assisted EG method, and colloidal method produced Pt/C catalysts with high dispersion and narrow particle size distribution of Pt NPs uniformly loaded on the carbon support. Au NPs with high dispersion and narrow particle size distribution can be made only by the colloidal method. AuPt/C catalysts were synthesized by two methods: physically by mixing Au NPs prepared by the colloidal method on Pt/C prepared by the EG method, and chemically by surface redox reactions of a Au precursor on Pt NPs prepared by the EG method and then loaded on the carbon support (denoted as AuPtC-EG-SR). The existence of Au on Pt/C was confirmed by EDX and by a larger ring current from ORR experiment using a rotating ring-disk electrode. Three membrane electrode assemblies (MEA) with commercial Etek Pt/C and those two types of AuPt/C catalysts as cathode catalyst respectively were fabricated for CSC comparison. Larger ECSA but less CO2 intensity of the MEA with a AuPtC-EG-SR cathode than those of the MEA with Etek Pt/C gives preliminary confirmation of the hypothesis.
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 Synthesis and Characterization of Nanostructured Electrocatalysts by Hydrophobic Nanoreactor Templating written by Tobias Unmüssig and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Pem Fuel Cell Electrocatalysts and Catalyst Layers written by Jiujun Zhang and published by Springer. This book was released on 2016-04-01 with total page 1160 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proton exchange membrane (PEM) fuel cells promise clean energy converting devices with high efficiency and low to zero emissions. This book provides a comprehensive, in-depth survey of the field, presented by internationally renowned fuel cell scientists.
Download or read book In situ X ray Absorption and Electrochemical Study of Electrocatalysts for Polymer Electrolyte Membrane PEM Fuel Cells written by Rameshkrishnan Viswanathan and published by . This book was released on 2002 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 and Characterization of Nanostructured Electrocatalysts for Proton Exchange Membrane and Direct Methanol Fuel Cells written by Liufeng Xiong and published by . This book was released on 2004 with total page 344 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proton exchange membrane fuel cells (PEMFC) and direct methanol fuel cells (DMFC) are attractive power sources as they offer high conversion efficiencies with low or no pollution. However, the most commonly used platinum electrocatalyst is expensive and the world supply of Pt is limited. In addition, the slow oxygen reduction and methanol oxidation kinetics as well as the poisoning of the Pt catalyst at the cathode resulting from methanol permeation from the anode through the Nafion membrane to the cathode lead to significant performance loss. Also, the electrocatalyst utilization in the electrodes also needs to be improved to reduce the overall cost of the electrocatalysts and improve the fuel cell performance. This dissertation explores nanostructured Pt alloys with lower cost and higher catalytic activity than Pt for oxygen reduction in PEMFC to understand the effect of synthesis and structure on the catalytic activity, methanol tolerant Pt/TiOx nanocomposites for oxygen reduction in DMFC, nanostructured Pt-Ru alloys for methanol oxidation in DMFC, and improvement in the utilization of Pt by optimizing the membrane-electrode assembly (MEA) fabrication. From a systematic investigation of a series of Pt-M alloys (M = Fe, Co, Ni, and Cu), the catalytic activity of Pt-M alloys is correlated with the extent of atomic ordering. More ordered Pt alloys exhibit higher catalytic activity than disordered Pt alloys. The higher activity of the ordered Pt alloys is found to relate to various factors including the Pt-Pt distance, Pt: 5d orbital vacancy, {100} planar density and surface atomic configuration. The catalytic activity of the Pt alloys is also influenced by the synthesis method. Low temperature solution methods usually result in smaller particle size and higher surface area, while high temperature routes result in larger particle size and lower surface area but with a greater extent of alloying. Pt/TiOx/C nanocomposites exhibit higher performance than Pt for oxygen reduction in DMFC. The nanocomposites show higher electrchochemical surface area, lower charge transfer resistance, and higher methanol tolerance than Pt. Pt-Ru alloy synthesized by a reverse microemulsion method exhibits higher catalytic surface area than the commercial Pt-Ru. The higher catalytic activity is attributed to a better control of the particle size, crystallinity, and microstructure. Membrane-electrode assemblies (MEAs) fabricated by a modified thin film method exhibit much higher electrocatalyst utilization efficiency and performance than the conventional MEAs in PEMFC. Power densities of 715 and 610 mW/cm2 are obtained at a Pt loading of, respectively, 0.1 and 0.05 mg/cm2 and 90 oC. The higher electrocatalyst utilization is attributed to the thin catalyst layer and a better continuity of the membrane/catalysts layer interface compared to that in the conventional MEAs.
Download or read book Analysis of the Electrochemical Characteristics of a Direct Methanol Fuel Cell Based on a Pt Ru C Anode Catalyst written by and published by . This book was released on 1996 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper deals with a vapour-feed direct methanol fuel cell (DMFC) based on a Nafion 117{reg_sign} solid polymer electrolyte. Pt-Ru/C and Pt/C catalysts were employed for methanol oxidation and oxygen reduction, respectively. Structure and surface chemistry of catalysts were investigated by X-ray powder diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Membrane/electrode assembly (M & E) was prepared by using a {open_quotes}paste process{close_quotes} method. Electrical power densities of about 150 mW cm−2 were obtained at 95° C with Pt loadings of 0.8 and 0.5 mg cm−2 at anode and cathode respectively.
