Fuel processing for low-temperature and high-temperature fuel cells: Challenges, and opportunities for sustainable development in the 21st century
TL;DR: In this article, the authors discuss the needs for fundamental changes in the energy system for major efficiency improvements in terms of global resource limitation and sustainable development, and discuss the strategies and options of fuel processors depend on the type of fuel cells and applications.
About: This article is published in Catalysis Today.The article was published on 2002-12-01. It has received 1106 citations till now. The article focuses on the topics: Regenerative fuel cell & Hydrogen fuel.
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TL;DR: A review of technologies related to hydrogen production from both fossil and renewable biomass resources including reforming (steam, partial oxidation, autothermal, plasma, and aqueous phase) and pyrolysis is presented in this article.
2,673 citations
TL;DR: Newly developed, high-conductivity electrolytes and nanostructured electrode designs provide a path for further performance improvement at much lower temperatures, down to ~350°C, thus providing opportunity to transform the way the authors convert and store energy.
Abstract: Fuel cells are uniquely capable of overcoming combustion efficiency limitations (e.g., the Carnot cycle). However, the linking of fuel cells (an energy conversion device) and hydrogen (an energy carrier) has emphasized investment in proton-exchange membrane fuel cells as part of a larger hydrogen economy and thus relegated fuel cells to a future technology. In contrast, solid oxide fuel cells are capable of operating on conventional fuels (as well as hydrogen) today. The main issue for solid oxide fuel cells is high operating temperature (about 800°C) and the resulting materials and cost limitations and operating complexities (e.g., thermal cycling). Recent solid oxide fuel cells results have demonstrated extremely high power densities of about 2 watts per square centimeter at 650°C along with flexible fueling, thus enabling higher efficiency within the current fuel infrastructure. Newly developed, high-conductivity electrolytes and nanostructured electrode designs provide a path for further performance improvement at much lower temperatures, down to ~350°C, thus providing opportunity to transform the way we convert and store energy.
1,974 citations
TL;DR: In this article, the authors discuss the problems of sulfur reduction in highway and non-road fuels and present an overview of new approaches and emerging technologies for ultra-deep desulfurization of refinery streams for ultra clean (ultra-low-sulfur) gasoline, diesel fuels and jet fuels.
1,874 citations
TL;DR: In this paper, the authors proposed to use CO2 for environmentally-benign physical and chemical processing that adds value to the process, using CO2 as an alternate medium or solvent or co-reactant or a combination of them.
1,541 citations
TL;DR: It is reported that platinum atomically dispersed on α-molybdenum carbide (α-MoC) enables low-temperature (150–190 degrees Celsius), base-free hydrogen production through APRM, with an average turnover frequency reaching 18,046 moles of hydrogen per mole of platinum per hour.
Abstract: Polymer electrolyte membrane fuel cells (PEMFCs) running on hydrogen are attractive alternative power supplies for a range of applications, with in situ release of the required hydrogen from a stable liquid offering one way of ensuring its safe storage and transportation before use. The use of methanol is particularly interesting in this regard, because it is inexpensive and can reform itself with water to release hydrogen with a high gravimetric density of 18.8 per cent by weight. But traditional reforming of methanol steam operates at relatively high temperatures (200-350 degrees Celsius), so the focus for vehicle and portable PEMFC applications has been on aqueous-phase reforming of methanol (APRM). This method requires less energy, and the simpler and more compact device design allows direct integration into PEMFC stacks. There remains, however, the need for an efficient APRM catalyst. Here we report that platinum (Pt) atomically dispersed on α-molybdenum carbide (α-MoC) enables low-temperature (150-190 degrees Celsius), base-free hydrogen production through APRM, with an average turnover frequency reaching 18,046 moles of hydrogen per mole of platinum per hour. We attribute this exceptional hydrogen production-which far exceeds that of previously reported low-temperature APRM catalysts-to the outstanding ability of α-MoC to induce water dissociation, and to the fact that platinum and α-MoC act in synergy to activate methanol and then to reform it.
944 citations
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01 Jan 2000
TL;DR: In this paper, the first edition of this paper, the authors presented an analysis of fuel cell systems and their performance in terms of Molar Gibbs Free Energy Calculations (GFE) and Open Circuit Voltage.
Abstract: Preface. Foreword to the first edition. Acknowledgements. Abbreviations. Symbols. Introduction. Efficiency and Open Circuit Voltage. Operational Fuel Cell Voltages. Proton Exchange Membrane Fuel Cells. Alkaline Electrolyte Fuel Cells. Direct Methanol Fuel Cells. Medium and High Temperature Fuel Cells. Fuelling Fuel Cells. Compressors, Turbines, Ejectors, Fans, Blowers, and Pumps. Delivering Fuel Cell Power. Fuel Cell Systems Analysed. Appendix 1: Change in Molar Gibbs Free Energy Calculations. Appendix 2: Useful Fuel Cell Equations. Index.
4,202 citations
TL;DR: The observation that a solid-oxide fuel cell can be operated on dry hydrocarbons, including liquid fuels, without reforming, suggests that this type of fuel cell could provide an alternative to hydrogen-based fuel-cell technologies.
Abstract: The direct electrochemical oxidation of dry hydrocarbon fuels to generate electrical power has the potential to accelerate substantially the use of fuel cells in transportation and distributed-power applications1. Most fuel-cell research has involved the use of hydrogen as the fuel, although the practical generation and storage of hydrogen remains an important technological hurdle2. Methane has been successfully oxidized electrochemically3,4,5,6, but the susceptibility to carbon formation from other hydrocarbons that may be present or poor power densities have prevented the application of this simple fuel in practical applications1. Here we report the direct, electrochemical oxidation of various hydrocarbons (methane, ethane, 1-butene, n-butane and toluene) using a solid-oxide fuel cell at 973 and 1,073 K with a composite anode of copper and ceria (or samaria-doped ceria). We demonstrate that the final products of the oxidation are CO2 and water, and that reasonable power densities can be achieved. The observation that a solid-oxide fuel cell can be operated on dry hydrocarbons, including liquid fuels, without reforming, suggests that this type of fuel cell could provide an alternative to hydrogen-based fuel-cell technologies.
1,717 citations
TL;DR: In this paper, the authors discuss the advantages and disadvantages of both low-temperature and high temperature fuel cells and propose a modularization of fuel cells, which makes them quite flexible as the power needed can easily be attained by changing the number of modules.
Abstract: Fuel cells will make a valuable contribution to future power generation facilities. They improve the flexibility and increase the options for many applications, such as distributed power, vehicle propulsion, and portable devices. Their main property is the high electrical efficiency compared to other energy conversion devices. Both the low-temperature and the high-temperature fuel cells have their advantages and disadvantages depending on the application. Sometimes, they can both be implemented in similar applications. The modularity of fuel cells makes them quite flexible as the power needed can easily be attained by changing the number of modules. Twenty years ago, mainly universities and research institutions but only a few companies conducted fuel cell research working on the fundamentals of fuel cells. Nowadays due to the commercial interest innumerable research groups and companies have fuel cell activities ranging from the investigation of catalysts (both improving existing catalyst systems as searching for new catalysts), the development of novel membranes for PEMFCs and DMFCs, to the development of other components for fuel cells. Optimisation of flow field structures, backing layers, and other components of the single cells have intensified. (orig.)
1,392 citations
TL;DR: A status report on development of the direct methanol fuel cell (DMFC) and relevant fundamental and applied electrochemistry is the objective of as discussed by the authors, where emphasis is put on strategies and approaches rather than on individual results.
1,217 citations