Robust Platinum Based Electrocatalysts For Fuel Cell Applications

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Robust Platinum-based Electrocatalysts for Fuel Cell Applications

Author : Eric James Coleman
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (923 download)

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Book Synopsis Robust Platinum-based Electrocatalysts for Fuel Cell Applications by : Eric James Coleman

Download or read book Robust Platinum-based Electrocatalysts for Fuel Cell Applications written by Eric James Coleman and published by . This book was released on 2015 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Polymer electrolyte fuel cells (PEMFCs) are energy conversion devices that exploit the energetics of the reaction between hydrogen fuel and O2 to generate electricity with water as the only byproduct. PEMFCs have attracted substantial attention due to their high conversion efficiency, high energy density, and low carbon footprint. However, PEMFC performance is hindered by the high activation barrier and slow reaction rates at the cathode where O2 undergoes an overall 4-electron reduction to water. The most efficient oxygen reduction reaction (ORR) catalyst materials to date are Pt group metals due to their high catalytic activity and stability in a wide range of operating conditions. Before fuel cells can become economically viable, efforts must be taken to decrease Pt content while maintaining a high level of ORR activity. This work describes the design and synthesis of a Pt-Cu electrocatalyst with ORR activity exceeding that of polycrystalline Pt. Production of this novel catalyst is quite simple and begins with synthesis of a porous Cu substrate, formed by etching Al from a Cu-Al alloy. The porous Cu substrate is then coated with a Pt layer via a spontaneous electrochemical process known as galvanic replacement. The Pt layer enhances the ORR activity (as measured by a rotating ring-disk electrode (RRDE)) and acts as a barrier towards corrosion of the Cu understructure. Growth of the Pt layer can be manipulated by time, temperature, concentration of Pt precursor, and convection rate during galvanic replacement. Data from analytical and electrochemical techniques confirm multiple Pt loadings have been achieved via the galvanic replacement process. The boost in ORR activity for the PtCu catalyst was determined to be a result of its lower affinity towards (site-blocking) OH adsorption. A unique catalyst degradation study explains the mechanism of initial catalyst ORR deactivation for both monometallic and bimetallic Pt-based catalysts. Finally, a rigorous and pioneering examination of how Pt surface passivation affects ORR dynamics is presented.

PEM Fuel Cell Electrocatalysts and Catalyst Layers

Author : Jiujun Zhang
Publisher : Springer Science & Business Media
ISBN 13 : 1848009364
Total Pages : 1147 pages
Book Rating : 4.8/5 (48 download)

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Book Synopsis PEM Fuel Cell Electrocatalysts and Catalyst Layers by : Jiujun Zhang

Download or read book PEM Fuel Cell Electrocatalysts and Catalyst Layers written by Jiujun Zhang and published by Springer Science & Business Media. This book was released on 2008-08-26 with total page 1147 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proton exchange membrane (PEM) fuel cells are promising clean energy converting devices with high efficiency and low to zero emissions. Such power sources can be used in transportation, stationary, portable and micro power applications. The key components of these fuel cells are catalysts and catalyst layers. “PEM Fuel Cell Electrocatalysts and Catalyst Layers” provides a comprehensive, in-depth survey of the field, presented by internationally renowned fuel cell scientists. The opening chapters introduce the fundamentals of electrochemical theory and fuel cell catalysis. Later chapters investigate the synthesis, characterization, and activity validation of PEM fuel cell catalysts. Further chapters describe in detail the integration of the electrocatalyst/catalyst layers into the fuel cell, and their performance validation. Researchers and engineers in the fuel cell industry will find this book a valuable resource, as will students of electrochemical engineering and catalyst synthesis.

Durable Fuel Cell Electrocatalysts for Energy Conversion

Author : Zishuai Zhang
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (119 download)

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Book Synopsis Durable Fuel Cell Electrocatalysts for Energy Conversion by : Zishuai Zhang

Download or read book Durable Fuel Cell Electrocatalysts for Energy Conversion written by Zishuai Zhang and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Electrocatalysts play an important avenue in clean and efficient energy conversion. Of the many electrocatalytic processes, the oxygen reduction reaction (ORR) attracts increasing attention due to its widespread importance in electrochemical cells. One of the most important applications is in proton-exchange membrane fuel cells (PEMFCs), which are considered as a promising power generation system because of its low operating temperature (70-90 ̊C), sustainable energy sources (hydrogen) and high energy efficiency. ORR is a key half reaction that takes place at the cathode with sluggish kinetics and requires noble metal (e.g. platinum)-based electrocatalysts to increase the reaction rate to attain practically usable levels. High cost and poor durability are major drawbacks of the commercial platinum on carbon (Pt/C) catalyst, and the corrosion of the carbon supports is considered one of the main reasons for the loss of expensive Pt, resulting in loss of performance of PEMFC. Therefore, more corrosion resistant, electrochemically stable and low-cost supports are highly desired for PEMFCs’ improved performance.Methanol oxidation reaction (MOR) is an anodic half reaction occurs at anodes of methanol fuel cells. Pt/C catalyst is also commonly used for that reaction. This thesis attempts to rationally design and synthesize various different nanostructured alternatives to carbon black for ORR and MOR. Graphene, a high conductive and stable two-dimensional carbon support, was successfully exfoliated electrochemically with little defects. Platinum (Pt) nanoparticles were deposited on graphene via double-pulse deposition technique. The catalyst was demonstrated to be highly efficient for MOR with a 920 mA/mg forward current density.Durable carbon nanotube (CNT) microspheres were synthesized through a facile and scalable ultrasonic bonding method without any binder or surfactant. The CNT microspheres with electrodeposited Pt were showcased as efficient ORR catalyst supports which showed no degradation after 12, 000 cycles (26.6 h). Furthermore, a soluble acicular calcium carbonate (aragonite, diameter 100 nm; length 800 nm) was used to created connected porosity in the microspheres to improve the mass transfer as the thickness increases. As for the ORR catalysis performance, the Pt decorated microspheres with macropores was 3.4 times higher (specific activity at 0.9V vs RHE) than non-macroporous microspheres with the identical Pt loading.Besides carbon-based supports, TiC was investigated as a potential carbon alternative due to its metallic electrical conductivity and excellent corrosion resistance. A cobalt oxide shell with high ORR activity was deposited onto TiC to improve its stability at high potential. We demonstrated that the oxide anchored Pt on TiC catalysts exhibited excellent durability (~100% catalytic activity remained at 0.1M KOH, and ~92% catalytic activity remained at 0.1M HClO4 after 16.7 h) compared to the Pt/C (~50% remained in both alkaline and acidic solutions). As assessed by transmission electron microscope (TEM), no significant Pt detachment or agglomeration was observed in oxide anchored catalysts, while heavily agglomeration has occurred to Pt/C.Hematene, two-dimensional layer of hematite (Fe2O3), has recently been exfoliated by means of liquid exfoliation. As the biodegradable metal, Fe-based materials attracts lots of attentions due to their ability to be entirely dissolved and cleared from the body. Electronics comprised of biodegradable metals can be programmed to degrade after the implantation. Here, we fabricated potentially biodegradable electrodes by using Au and hematene for glucose oxidation. It showed 9.5 mA/mgAu oxidation current density at the potential of 0.6V (vs. RHE), and high stability during the continuous cell cycling. Additionally, the prepared catalyst exhibited short response time and linear calibration range"--

Electrocatalysis in Fuel Cells

Author : Minhua Shao
Publisher : Springer Science & Business Media
ISBN 13 : 1447149114
Total Pages : 748 pages
Book Rating : 4.4/5 (471 download)

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Book Synopsis Electrocatalysis in Fuel Cells by : Minhua Shao

Download or read book Electrocatalysis in Fuel Cells written by Minhua Shao and published by Springer Science & Business Media. This book was released on 2013-04-08 with total page 748 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fuel cells are one of the most promising clean energy conversion devices that can solve the environmental and energy problems in our society. However, the high platinum loading of fuel cells - and thus their high cost - prevents their commercialization. Non- or low- platinum electrocatalysts are needed to lower the fuel cell cost. Electrocatalysis in Fuel Cells: A Non and Low Platinum Approach is a comprehensive book summarizing recent advances of electrocatalysis in oxygen reduction and alcohol oxidation, with a particular focus on non- and low-Pt electrocatalysts. All twenty four chapters were written by worldwide experts in their fields. The fundamentals and applications of novel electrocatalysts are discussed thoroughly in the book. The book is geared toward researchers in the field, postgraduate students and lecturers, and scientists and engineers at fuel cell and automotive companies. It can even be a reference book for those who are interested in this area.

Platinum Monolayer Electrocatalysts

Author : Radoslav Adzic
Publisher : Springer Nature
ISBN 13 : 3030495663
Total Pages : 174 pages
Book Rating : 4.0/5 (34 download)

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Book Synopsis Platinum Monolayer Electrocatalysts by : Radoslav Adzic

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.

Durable Pt-based Catalysts for Oxygen Reduction Reaction in Fuel Cell

Author : Zeyan Liu
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (139 download)

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Book Synopsis Durable Pt-based Catalysts for Oxygen Reduction Reaction in Fuel Cell by : Zeyan Liu

Download or read book Durable Pt-based Catalysts for Oxygen Reduction Reaction in Fuel Cell written by Zeyan Liu and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fuel cells are devices that can efficiently convert fuels into electricity without the limitation of the Carnot cycle. Particularly, hydrogen fuel cells have attracted enormous interest due to their high energy density, high efficiency, and low environmental impacts. The most widely adopted proton-exchange-membrane fuel cells (PEMFCs) use platinum (Pt) catalysts to drive both anode and cathode reactions. To date, the most significant roadblock to the broad dissemination of this green energy technology remains the acceleration and retention of the reaction rate of oxygen reduction reaction (ORR) at the cathode. Developing robust, active, and cost-effective ORR catalysts is the solution to this challenge.In my first work, I demonstrated a Cu doping strategy to enhance the intrinsic activity and durability of octahedral PtNi nanoparticles in the rotating-disk-electrode (RDE) setting. By a novel integration of simulations and growth tracking experiments, we uncover the beneficial role of increased surface Pt composition, which reduces the generation of surface vacancies and subsequent dissolution of sub-surface Cu and Ni atoms. Unlike the well-controlled RDE system, the critical role of mass transports in a practical membrane-electrode-assembly (MEA) system demands additional consideration in stability-enhancing strategies. Therefore, in my subsequent work, I recognized the critical challenge in MEA with ultralow Pt loading and designed a graphene-nanopocket-encaged platinum cobalt nanocatalyst with good electrochemical accessibility and exceptional durability in practical MEA testing. With the greatly improved rated power and durability, a 6.8 gram Pt loading is projected for a 90-kW PEMFC light-duty vehicle, approaching that used in a typical catalytic converter. Furthermore, I presented a unique design of ultrafine Pt nanocatalysts with embedded cobalt oxide clusters, which further improve the catalyst stability for durable PEMFCs. This endohedral-oxide design exploits the strong Pt/oxide interaction, which grants the catalyst its exceptional structural and chemical durability, without sacrificing activity. The developed nanocatalyst exhibits exceptional durability promising an outstanding projected lifetime of 15,000 hours.

Rational Design of Efficient and Durable Pt-based Electrocatalysts for Fuel Cells

Author : Bosi Peng
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (139 download)

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Book Synopsis Rational Design of Efficient and Durable Pt-based Electrocatalysts for Fuel Cells by : Bosi Peng

Download or read book Rational Design of Efficient and Durable Pt-based Electrocatalysts for Fuel Cells written by Bosi Peng and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proton exchange membrane fuel cells (PEMFCs) offer an attractive zero-emission power generation technology to realize a carbon-neutral future. However, the competitiveness of PEMFCs is severely constrained by the costly precious metal catalysts needed for the cathode oxygen reduction reaction (ORR). This thesis aims to address two critical challenges in ORR catalysts, activity and durability. To this end, we first developed a facile molecular surface modification approach using dimethylformamide to improve the microkinetics of the physisorption/desorption process in ORR, to achieve an unprecedented specific activity of 21.8 mA/cm2 in modified model PtCuNi catalyst. Next, by exploiting a unique design of jagged Pt nanowire catalysts, we developed a high-performance PEMFC using PtCo nanowire catalysts to realize an unprecedented mass activity of 1.06 A/mgPt, far surpassing the Department of Energy target. Lastly, exploiting a strong-metal-oxide binding effect, we further designed a unique ultrafine Pt nanocatalysts with embedded cobalt oxide to achieve superior power performance and life durability. These studies offer new perspectives on fuel cell catalyst design and hold significant promise to substantially reduce the lifetime adjusted cost for widespread adoption of PEMFCs in practical technologies.

Nanomaterials for Direct Alcohol Fuel Cells

Author : Fatih Sen
Publisher : Elsevier
ISBN 13 : 0128217146
Total Pages : 552 pages
Book Rating : 4.1/5 (282 download)

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Book Synopsis Nanomaterials for Direct Alcohol Fuel Cells by : Fatih Sen

Download or read book Nanomaterials for Direct Alcohol Fuel Cells written by Fatih Sen and published by Elsevier. This book was released on 2021-08-25 with total page 552 pages. Available in PDF, EPUB and Kindle. Book excerpt: Nanomaterials for Direct Alcohol Fuel Cells explains nanomaterials and nanocomposites as well as the characterization, manufacturing, and design of alcohol fuel cell applications. The advantages of direct alcohol fuel cells (DAFCs) are significant for reliable and long-lasting portable power sources used in devices such as mobile phones and computers. Even though substantial improvements have been made in DAFC systems over the last decade, more effort is needed to commercialize DAFCs by producing durable, low-cost, and smaller-sized devices. Nanomaterials have an important role to play in achieving this aim. The use of nanotechnology in DAFCs is vital due to their role in the synthesis of nanocatalysts within the manufacturing process. Lately, nanocatalysts containing carbon such as graphene, carbon nanotubes, and carbon nanocoils have also attracted much attention. When compared to traditional materials, carbon-based materials have unique advantages, such as high corrosion resistance, better electrical conductivity, and less catalyst poisoning. This book also covers different aspects of nanocomposites fabrication, including their preparation, design, and characterization techniques for their fuel cell applications. This book is an important reference source for materials scientists, engineers, energy scientists, and electrochemists who are seeking to improve their understanding of how nanomaterials are being used to enhance the efficiency and lower the cost of DAFCs. Shows how nanomaterials are being used for the design and manufacture of DAFCs Explores how nanotechnology is being used to enhance the synthesis and catalysis processes to create the next generation of fuel cells Assesses the major challenges of producing nanomaterial-based DAFCs on an industrial scale

Polymer Electrolyte Fuel Cells

Author : Alejandro A. Franco
Publisher : CRC Press
ISBN 13 : 9814310824
Total Pages : 618 pages
Book Rating : 4.8/5 (143 download)

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Book Synopsis Polymer Electrolyte Fuel Cells by : Alejandro A. Franco

Download or read book Polymer Electrolyte Fuel Cells written by Alejandro A. Franco and published by CRC Press. This book was released on 2013-07-09 with total page 618 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book focuses on the recent research progress on the fundamental understanding of the materials degradation phenomena in PEFC, for automotive applications. On a multidisciplinary basis, through contributions of internationally recognized researchers in the field, this book provides a complete critical review on crucial scientific topics related to PEFC materials degradation, and ensures a strong balance between experimental and theoretical analysis and preparation techniques with several practical applications for both the research and the industrial communities.

Spontaneous Incorporation of Gold in Palladium-based Ternary Nanoparticles Makes Durable Electrocatalysts for Oxygen Reduction Reaction

Download Spontaneous Incorporation of Gold in Palladium-based Ternary Nanoparticles Makes Durable Electrocatalysts for Oxygen Reduction Reaction PDF Online Free

Author :
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (967 download)

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Book Synopsis Spontaneous Incorporation of Gold in Palladium-based Ternary Nanoparticles Makes Durable Electrocatalysts for Oxygen Reduction Reaction by :

Download or read book Spontaneous Incorporation of Gold in Palladium-based Ternary Nanoparticles Makes Durable Electrocatalysts for Oxygen Reduction Reaction written by and published by . This book was released on 2016 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Replacing platinum by a less precious metal such as palladium, is highly desirable for lowering the cost of fuel-cell electrocatalysts. However, the instability of palladium in the harsh environment of fuel-cell cathodes renders its commercial future bleak. Here in this paper, we show that by incorporating trace amounts of gold in palladium-based ternary (Pd6CoCu) nanocatalysts, the durability of the catalysts improves markedly. Using aberration-corrected analytical transmission electron microscopy in conjunction with synchrotron X-ray absorption spectroscopy, we show that gold not only galvanically replaces cobalt and copper on the surface, but also penetrates through the Pd-Co-Cu lattice and distributes uniformly within the particles. The uniform incorporation of Au provides a stability boost to the entire host particle, from the surface to the interior. The spontaneous replacement method we have developed is scalable and commercially viable. In conclusion, this work may provide new insight for the large-scale production of non-platinum electrocatalysts for fuel-cell applications.

Strong metal-support interaction of Pt-based electrocatalysts with transition metal oxides/nitrides/carbides for oxygen reduction reaction

Download Strong metal-support interaction of Pt-based electrocatalysts with transition metal oxides/nitrides/carbides for oxygen reduction reaction PDF Online Free

Author : Min Chen
Publisher : OAE Publishing Inc.
ISBN 13 :
Total Pages : 31 pages
Book Rating : 4./5 ( download)

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Book Synopsis Strong metal-support interaction of Pt-based electrocatalysts with transition metal oxides/nitrides/carbides for oxygen reduction reaction by : Min Chen

Download or read book Strong metal-support interaction of Pt-based electrocatalysts with transition metal oxides/nitrides/carbides for oxygen reduction reaction written by Min Chen and published by OAE Publishing Inc.. This book was released on 2023-06-06 with total page 31 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Synthesis and Characterization of Pt/TiO2/C Composite Catalysts for Fuel Cells Prepared Using a Glucose Modifier

Author : Christopher Odetola
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (134 download)

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Book Synopsis Synthesis and Characterization of Pt/TiO2/C Composite Catalysts for Fuel Cells Prepared Using a Glucose Modifier by : Christopher Odetola

Download or read book Synthesis and Characterization of Pt/TiO2/C Composite Catalysts for Fuel Cells Prepared Using a Glucose Modifier written by Christopher Odetola and published by . This book was released on 2017 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Catalysts in the electrodes of polymer exchange membrane fuel cells (PEMFCs) serve a critical function in reactions which can be used to generate electrical energy from chemical fuels. Pt nanoparticles are commonly dispersed on a conductive support and used as electrode materials in these devices because of their exceptional catalytic activity and electrochemical active surface area. The performance and stability of these electrodes strongly depend on the characteristics of the support. Catalysts supported on high surface area carbon black are widely used in low-temperature fuel cells. In PEMFCs, these catalyst materials can be exposed to high potential and low pH values, resulting in irreversible loss of activity that will limit the useful lifetime of the cell, ultimately leading to its failure. Pt is a noble metal which has good intrinsic stability, but carbon is not thermodynamically stable resulting in the corrosion of the catalyst support under these conditions. The design of more resilient platinum catalyst supports to carry out the successful reaction in a fuel cell's catalyst layer is required to extend the lifetime of PEMFCs degradation. In this thesis, two approaches were used to synthesize robust catalyst support materials for fuel cell applications. In the first case, carbon surfaces were functionalised to enhance their interactions with the catalyst and secondly, stable metal oxide was combined with modified carbon substrates, to maximise contacts within the composite electrocatalysts and to prevent carbon corrosion of a single phase carbon support catalyst. TiO2 NPs, were first chemically bonded to the surfaces of Vulcan carbon to help anchor the Pt catalyst nanoparticles through strong metal-support interactions. Validation of a dual phase catalyst support is an important goal of this research. Each material phase offers a unique advantage that can only be recognized by the preparation of a composite electrocatalyst. Pristine Vulcan (PV) was functionalised with glucose hydroxyl functional groups that react with the base titanium metal alkoxide in a sol-gel reaction and then calcined to form a more chemically crystalline surface. This is followed by impregnation reduction process to deposit the nanostructured Pt catalyst. Material characterization data of synthesized materials were used to correlate the effects of support structure and composition on resilient performance. Advantages from the TiO2/C supports toward performance and durability were contrasted against a set of control samples and demonstrated ex situ. The prepared composite catalysts showed substantial enhancements toward oxygen reduction reaction (ORR) and methanol oxidation reaction (MOR) as well as improved stability of the Pt-TiO2 heterogeneous interface formed between catalyst and support. The enhanced performance and durability of these composite catalysts is improved by applying the science of materials and interfaces to the synthesis of composite supports, thus serving as an example for further progress and optimization. Irradiation of these composite catalysts with UV-visible light also showed ~ 171 % photo enhanced activity for MOR, which clearly demonstrates a synergistic effect between the photo- and electrocatalysts. The comparison between the prepared catalysts indicates that there is an appropriate ratio of carbon and TiO2 to obtain the best performance of these photoelectroactive materials. These results demonstrate that methanol oxidation is achieved by electro- and photoelectrocatalysis using a simple and affordable method. This procedure can be conveniently exploited to enhance the response of direct methanol fuel cell electrodes.

Electrocatalytic Property of Facet-controlled Platinum Alloy Fuel Cell Catalysts

Author : Jianbo Wu
Publisher :
ISBN 13 :
Total Pages : 217 pages
Book Rating : 4.:/5 (93 download)

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Book Synopsis Electrocatalytic Property of Facet-controlled Platinum Alloy Fuel Cell Catalysts by : Jianbo Wu

Download or read book Electrocatalytic Property of Facet-controlled Platinum Alloy Fuel Cell Catalysts written by Jianbo Wu and published by . This book was released on 2012 with total page 217 pages. Available in PDF, EPUB and Kindle. Book excerpt: "With rapid depletion of fossil fuel and the increasing concern over CO2 release, there is an urgent need to develop a new technology using alternative energy sources. Polymer electrolyte membrane fuel cell (PEMFC) is considered one of the promising technologies due to their high energy efficiency, and environmental friendliness. Platinum has been widely used as electrocatalyst in PEMFCs because of its ability to absorb and dissociate important chemical species, such as hydrogen and oxygen. The high cost of platinum used in the electrocatalysts however hinders the real world applications of PEMFCs. It is critical that consumption of platinum be reduced without sacrificing catalytic performance. Highly active and durable electrocatalysts with low Pt content need to be developed in order to advance the fuel cell technology. Studies have demonstrated that both d-band electron and surface geometric structure can greatly affect the activity of catalysts and be optimized by tailoring their composition and surface. In this thesis I present the synthesis, characterization and electrochemical property of facet-controlled platinum bimetallic alloy nanoparticles. A series of Pt-M (M= Co, Cu, Fe, Ni and Pd) bimetallic alloys with various shapes bounded with {111} or {100} facets have been prepared and their electrocatalytic properties have been tested. The surface-defined Pt3Ni nanocrystals have exhibited enhanced activity in oxygen reduction reaction (ORR), which is proportional to the surface ratio of {111} over {100} facets, when the shape of Pt3Ni nanocrystals changes gradually from cube to truncated octahedron, and to octahedron. Beyond the shape-controlled synthetic approach assisted by commonly used capping agents and reducing agents to produce bimetallic alloy nanocrystals with different compositions. CO, a gaseous reducing agent, was introduced to control the morphology of platinum alloys. Electrochemical stripping and Fourier transform infrared spectroscopy (FTIR) were used to show the strong facet-sensitive adsorption and oxidation play the key roles for the shape-controlled synthesis. This facet-preferential adsorption and oxidation property was also applied to address the issue on CO poisoning in methanol oxidation reaction (MOR). The size-dependent ORR catalytic properties of {111} surface-dominated octahedral Pt3Ni nanocrystals were examined in order to narrow the gap in ORR activity shown between the nanocrystal catalysts and extended single crystal surface of Pt3Ni alloys. The area-specific ORR activities of Pt3Ni catalysts at 0.9 V were 0.85 mA/cm2 Pt for the nanocubes, and 1.26 mA/cm2 Pt for the nanooctahedra. The ORR mass activity of the octahedral Pt3Ni catalyst reached 0.44 A/mg Pt. Pt-M (M = Au, Ni, Pd) alloy icosahedral nanocrystals was obtained based on CO assisted reduction methods. The area specific activity of icosahedral Pt3Ni catalysts (1.82 mA/cm2Pt) was about 50% higher than that of the octahedral (1.26 mA/cm2Pt), even though both shapes are bounded by {111} facets. Density functional theory (DFT) calculation and molecular dynamic simulation results showed that this improvement may come from strain-induced electronic effects. A quantitative surface segregation model on durability of bimetallic alloy ORR catalysts was established by studying the anisotropic diffusion coefficient, diffusion length and atomic size of non-platinum metals"--Pages v-vi.

PEM Fuel Cells

Author : Gurbinder Kaur
Publisher : Elsevier
ISBN 13 : 0128237090
Total Pages : 584 pages
Book Rating : 4.1/5 (282 download)

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Book Synopsis PEM Fuel Cells by : Gurbinder Kaur

Download or read book PEM Fuel Cells written by Gurbinder Kaur and published by Elsevier. This book was released on 2021-11-16 with total page 584 pages. Available in PDF, EPUB and Kindle. Book excerpt: PEM Fuel Cells: Fundamentals, Advanced Technologies, and Practical Application provides a comprehensive introduction to the principles of PEM fuel cell, their working condition and application, and the latest breakthroughs and challenges for fuel cell technology. Each chapter follows a systematic and consistent structure with clear illustrations and diagrams for easy understanding. The opening chapters address the basics of PEM technology; stacking and membrane electrode assembly for PEM, degradation mechanisms of electrocatalysts, platinum dissolution and redeposition, carbon-support corrosion, bipolar plates and carbon nanotubes for the PEM, and gas diffusion layers. Thermodynamics, operating conditions, and electrochemistry address fuel cell efficiency and the fundamental workings of the PEM. Instruments and techniques for testing and diagnosis are then presented alongside practical tests. Dedicated chapters explain how to use MATLAB and COMSOL to conduct simulation and modeling of catalysts, gas diffusion layers, assembly, and membrane. Degradation and failure modes are discussed in detail, providing strategies and protocols for mitigation. High-temperature PEMs are also examined, as are the fundamentals of EIS. Critically, the environmental impact and life cycle of the production and storage of hydrogen are addressed, as are the risk and durability issues of PEMFC technology. Dedicated chapters are presented on the economics and commercialization of PEMFCs, including discussion of installation costs, initial capital costs, and the regulatory frameworks; apart from this, there is a separate chapter on their application to the automotive industry. Finally, future challenges and applications are considered. PEM Fuel Cells: Fundamentals, Advanced Technologies, and Practical Application provides an in-depth and comprehensive reference on every aspect of PEM fuel cells fundamentals, ideal for researchers, graduates, and students. Presents the fundamentals of PEM fuel cell technology, electrolytes, membranes, modeling, conductivity, recent trends, and future applications Addresses commercialization, public policy, and the environmental impacts of PEMFC in dedicated chapters Presents state-of-the-art PEMFC research alongside the underlying concepts

Advanced Electrocatalysts for Low-Temperature Fuel Cells

Author : Francisco Javier Rodríguez-Varela
Publisher : Springer
ISBN 13 : 3319990195
Total Pages : 318 pages
Book Rating : 4.3/5 (199 download)

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Book Synopsis Advanced Electrocatalysts for Low-Temperature Fuel Cells by : Francisco Javier Rodríguez-Varela

Download or read book Advanced Electrocatalysts for Low-Temperature Fuel Cells written by Francisco Javier Rodríguez-Varela and published by Springer. This book was released on 2018-10-09 with total page 318 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book introduces the reader to the state of the art in nanostructured anode and cathode electrocatalysts for low-temperature acid and alkaline fuel cells. It explores the electrocatalysis of anode (oxidation of organic molecules) and cathode (oxygen reduction) reactions. It also offers insights into metal-carbon interactions, correlating them with the catalytic activity of the electrochemical reactions. The book explores the electrocatalytic behaviour of materials based on noble metals and their alloys, as well as metal-metal oxides and metal-free nanostructures. It also discusses the surface and structural modification of carbon supports to enhance the catalytic activity of electrocatalysts for fuel-cell reactions.

Electrocatalysts for Fuel Cells and Hydrogen Evolution

Author : Abhijit Ray
Publisher : BoD – Books on Demand
ISBN 13 : 1789848121
Total Pages : 130 pages
Book Rating : 4.7/5 (898 download)

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Book Synopsis Electrocatalysts for Fuel Cells and Hydrogen Evolution by : Abhijit Ray

Download or read book Electrocatalysts for Fuel Cells and Hydrogen Evolution written by Abhijit Ray and published by BoD – Books on Demand. This book was released on 2018-12-05 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt: The book starts with a theoretical understanding of electrocatalysis in the framework of density functional theory followed by a vivid review of oxygen reduction reactions. A special emphasis has been placed on electrocatalysts for a proton-exchange membrane-based fuel cell where graphene with noble metal dispersion plays a significant role in electron transfer at thermodynamically favourable conditions. The latter part of the book deals with two 2D materials with high economic viability and process ability and MoS2 and WS2 for their prospects in water-splitting from renewable energy.

Non-precious Metal Based Electrocatalysts for Oxygen Reduction in Proton Exchange Membrane Fuel Cells and Electrolyzers

Author : Urszula Tylus
Publisher :
ISBN 13 :
Total Pages : 111 pages
Book Rating : 4.:/5 (898 download)

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Book Synopsis Non-precious Metal Based Electrocatalysts for Oxygen Reduction in Proton Exchange Membrane Fuel Cells and Electrolyzers by : Urszula Tylus

Download or read book Non-precious Metal Based Electrocatalysts for Oxygen Reduction in Proton Exchange Membrane Fuel Cells and Electrolyzers written by Urszula Tylus and published by . This book was released on 2014 with total page 111 pages. Available in PDF, EPUB and Kindle. Book excerpt: The oxygen reduction reaction (ORR) is a key process in various electrochemical energy conversion devices such as fuel cells and metal batteries as it enables CO2-free electrical energy generation. One of the major challenges in these devices is the sluggish kinetics of ORR and thus the need for stable and highly active electrocatalysts. The currently utilized catalytic materials are based on precious group metals (PGM), including platinum, rhodium, or silver. Although the PGM-based catalysts are highly active and reasonably stable under harsh acidic fuel cell conditions, the PGM-systems contribute to high cost of the energy conversion device. This is further aggravated by the high sensitivity of the PGM-catalysts to the presence of small amounts of impurities in the real world environment causing performance decay. These challenges pushed researchers to look for a cost-effective and highly active alternate catalyst materials based on non-precious group metals (non-PGM). Currently, the most promising non-PGM systems are comprised of transition metal-nitrogen-carbon (M-N-C) containing catalysts. Despite several decades of effort to obtain the "perfect" M-N-C catalyst, there is still a fair amount of work to be done mainly towards understanding the origin of ORR activity in these complex M-N-C systems. The objective in these studies is to design the optimal active structure that is able to provide high and selective performance sustained even in very corrosive environments. Element-specific in-situ X-ray absorption spectroscopy (XAS) coupled with standard electrochemical methodology (mainly Rotating Ring Disc Eelectrode, RRDE) is a great tool to study surface active catalytic systems. With a careful experimental design, "in-situ" XAS is able to provide very useful mechanistic information regarding structural properties of the active centers and their behavior in simulated electrochemical environments. Chapter 1 contains a brief description of fundamental aspects of the oxygen reduction reaction, and related challenges. This includes: electrolyte-dependent general description of the ORR mechanistic pathways, and currently known relations between electronic/structural properties of known PGM and non-PGM materials and their catalytic activity. The major electroanalytical and spectroscopic techniques are also discussed, aiming to provide introductory information to the reader needed to understand the experimental work discussed in the following chapters. As the main point of interest is ORR kinetics, which comprise the performance and degradation modes in an aqueous environment, Chapter 2 discusses comparative characteristics of mechanistic ORR pathways (in acid and alkaline media) with a group of the M-N-C catalysts synthesized via various routes. The electroanalytical studies shown in Chapter 2 are followed by more detailed mechanistic investigations (in Chapter 3) wherein the ORR kinetics on the M-N-C catalysts is investigated using "in-situ" spectro-electrochemical XAS methodologies of transition metal centers. Different forms of the metals and their mechanistic roles are investigated by ORR kinetic studies and behavioral monitoring after selective removal or blocking each of the moieties. The information obtained by the mechanistic studies are used in Chapter 4 to discuss the effect of chloride anions on the overall M-N-C activity with the aim to predict their potential use as O2-consuming cathodes in industrial environments involving presence of the chloride species, known to be a strong poison for platinum-based catalysts. Finally, Chapter 5 shows performance non-PGM catalysts developed at NEU based on carbon supported polymer and self-supported Metal Organic Framework (MOF) iron comprising M-N-C catalysts as oxygen depolarized cathodes for recycling of chlorine gas from hydrochloric acid, a common bi-product in industrial chemical plants. Chapter 5 discusses structure-property relationship of the M-N-C catalysts, and their iron-based active centers to overall catalytic performance and stability in such corrosive environment as concentrated hydrochloric acid. The Chapter 5 also covers a promising preliminary study of utilization of the M-N-C catalysts as Oxygen De-polarized Cathodes (ODC) in the chlor-alkali process for Cl2-production. Finally, Chapter 6 summarized the work presented here and discusses future perspectives for applications of the non-PGM catalysts.