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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 54 for “"Catalyst Layer"”.
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Catalyst Layer Design in Polymer Membrane Fuel Cells
… membrane fuel cells is the use of platinum as a catalyst. One way to overcome this obstacle is to replace platinum with non-platinum group metal (non-PGM) catalysts, particularly for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs). The most realistic method of …
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A Microstructural Model for a Proton Exchange Membrane Fuel Cell Catalyst Layer
… a framework for a microstructural model of a catalyst layer in a proton exchange membrane (PEM) fuel cell. In this study, a stochastic model that uses individual carbon, platinum and ionomer particles as building blocks to construct a catalyst layer geometry, resulting in optimal porosity and …
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Microscopic and spectroscopic characterization of fuel cell catalyst layer materials and interfaces
… the investigation of the role of defects at the catalyst layer/membrane interface, the degradation of alkaline fuel cell materials, and the investigation of catalyst ionomer distribution and catalyst ionomer interfaces within the catalyst layer. Chapter 3 investigates the properties of a series …
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Distributed Generation Reformer and Fuel Cell System Modeling and Reformer Catalyst Layer Optimization
… process. Parameter studies on the reformer catalyst layer showed that reducing catalyst layer porosity along the length of the reformer results in improved reformer performance because of increased catalyst mass and higher reaction rates downstream that help push the reforming reaction …
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Combining In Situ Measurements and Advanced Catalyst Layer Modeling in PEM Fuel Cells
Catalyst layer modeling can be a useful tool for fuel cell design. By comparing numerical results to experimental results, numerical models can provide a better understanding of the physical processes occurring within the fuel cell catalyst layer. This can lead to design optimization and cost …
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A Microscopic Continuum Model of a Proton Exchange Membrane Fuel Cell Electrode Catalyst Layer
… microscopic continuum models of the cathode catalyst layer (active layer) of a proton exchange membrane fuel cell are developed and presented. This model incorporates O₂ species and ion transport while taking a discrete look at the platinum particles within the active layer. The original …
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The Effect of Catalyst Layer Cracks on the Mechanical Fatigue of Membrane Electrode Assemblies
… influenced by the presence of mud cracks in the catalyst layers acting as stress concentrators. Fatigue testing of MEAs has shown that smaller-scale cracking occurs in the membrane within these mud cracks, leading to leaking during mechanical fatigue testing and the failure of the membrane. In …
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Modifications and studies of the anode catalyst layer for the direct formic acid fuel cell
… of the effect of Nafion® loading in the anode catalyst layer using electrochemical techniques. Nafion®, within the anode and cathode catalyst layers, plays a large role in the performance of fuel cells. Nafion® also serves as a binder to help hold the catalyst nanoparticles onto the proton …
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Influence of catalyst ink mixing procedures on catalyst layer properties and in-situ PEMFC performance
… been directed towards developing more active catalysts, the amount of catalyst required in the fuel cell can be further reduced by improving the platinum utilisation in the membrane electrode assembly. The platinum utilisation is a strong function of the catalyst layer preparation step and …
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Investigation of the Effect of Catalyst Layer Composition on the Performance of PEM Fuel Cells
The catalyst layer of a proton exchange membrane (PEM) fuel cell is a porous mixture of polymer, carbon, and platinum. The characteristics of the catalyst layer play a critical role in determining the performance of the PEM fuel cell. In this research, sample membrane electrode assemblies (MEAs) …
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EFFECT OF MECHANICAL VIBRATION ON PLATINUM PARTICLE AGGLOMERATION AND GROWTH IN PROTON EXCHANGE MEMBRANE FUEL CELL CATALYST LAYER
… to study the effect of mechanical vibration on catalyst layer degradation via Platinum (Pt) particle agglomeration and growth in the membrane electrode assembly (MEA) of a proton exchange membrane fuel cell (PEM Fuel Cell). This study is of great importance, since many PEM fuel cells operate …
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The effectivness of using a non-platinum material combination for the catalyst layer of a proton exchange membrane fuel cell
Submitted in the fulfilment of the requirements for the Master of Engineering, Durban University of Technology, Durban, South Africa, 2016.
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Transient Model of Heat,Mass,and Charge transfer as well as Electrochemistry in the Cathode Catalyst Layer of a PEMFC
A transient model of the cathode catalyst layer of a proton exchange membrane fuel cell is presented. The catalyst layer structure can be described as a superposition of the polymer membrane, the backing layer, and some additional platinum particles. The model, which incorporates some of the …
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Investigation into the behaviour of a wash-coated PGM-based catalyst layer onto micro-channel reactors for the steam reforming of methane
… originally been used for wash-coating a Rh/Al₂O₃ catalyst onto stainless steel micro-channels (MC) for the reforming of propane [24] was tested in the steam reforming of methane. The robustness of this method was unknown and was therefore tested for its possible application in methane steam …
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Experimental Investigation of the Effect of Composition on the Performance and Characteristics of PEM Fuel Cell Catalyst Layers
The catalyst layer of a proton exchange membrane (PEM) fuel cell is a mixture of polymer, carbon, and platinum. The characteristics of the catalyst layer play a critical role in determining the performance of the PEM fuel cell. This research investigates the role of catalyst layer composition using …
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Analysis of Ionomer-coated Carbon Nanofiber for use in PEM Fuel Cell Catalyst Layers
The typical catalyst layer structure for proton exchange membrane (PEM) fuel cells has changed little over the last two decades. A new electrode design with improved control over factors such as ionic and electrical pathways, porosity, and catalyst placement, could allow the application of less …
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Understanding the carbon morphology in sulfonated-silica ceramic carbon electrodes for the PEM fuel cell device
… is the use of the precious metal Pt within the catalyst layer. Efforts in decreasing the amount of Pt has provided information on improved utilization of the catalytic metal. Another limitation can be attributed to the perfluorosulfonated ionomer Nafion®, that is commercially available and used …
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Molecular simulation method development and implementation for fuel cell catalyst layers
… behaviour of a fuel cell, specifically a catalyst layer where the oxygen reduction reaction (ORR) takes place. The processes taking place in the catalyst layer are inefficient at ambient conditions and so this fuel cell component is, together with high price of platinum as the catalyst, …
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Development of a zeolite washcoating technique for microchannel reactors
… microreactor technology is the requirement of a catalyst layer.
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The design of a microfabricated air electrode for liquid electrolyte fuel cells
… electrode for liquid electrolyte fuel cells. The catalyst layer of the electrode is envisioned to be fabricated by using a microfabricated die to apply a three-dimensionally patterned macro-texture upon a microporous carbon matrix. The resulting dual porosity structure consists of an array of …
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