Polymer electrolyte fuel cell anode, 463

K. Karan. Assessment of transport-limited catalyst utilization for engineering of ultra-low Pt loading polymer electrolyte fuel cell anode. Electrochem. Comm., 9 747-753, 2007. 

Polymer Electrolyte Fuel Cell. The electrolyte in a PEFC is an ion-exchange (qv) membrane, a fluorinated sulfonic acid polymer, which is a proton conductor (see Membrane technology). The only Hquid present in this fuel cell is the product water thus corrosion problems are minimal. Water management in the membrane is critical for efficient performance. The fuel cell must operate under conditions where the by-product water does not evaporate faster than it is produced because the membrane must be hydrated to maintain acceptable proton conductivity. Because of the limitation on the operating temperature, usually less than 120°C, H2-rich gas having Htde or no (

Polymer electrolyte fuel cells (PEFCs) have attracted great interest as a primary power source for electric vehicles or residential co-generation systems. However, both the anode and cathode of PEFCs usually require platinum or its alloys as the catalyst, which have high activity at low operating temperatures (<100 °C). For large-scale commercialization, it is very important to reduce the amount of Pt used in fuel cells for reasons of cost and limited supply. 

Watanabe M, Igarashi H, Fujino T. 1999. Design of CO tolerant anode catalysts for polymer electrolyte fuel cell. Electrochemistry 67 1194-1196. 

Diemant T, Hager T, Hosier HE, Rauscher H, Behm RJ. 2003. Hydrogen adsorption and coadsorption with CO on well-defined himetallic PtRu surfaces—A model study on the CO tolerance of himetallic PtRu anode catalysts in low temperature polymer electrolyte fuel cells. Surf Sci 541 137. 

Muhamad, E.N., Takeguchi, T., Wang, G., Anzai, Y., and Ueda, W. (2009) Electrochemical characteristics of Pd anode catalyst modified with Ti02 nanoparticles in polymer electrolyte fuel cell. Journal of the Electrochemical Society, 156 (1), B32-B37. 

One particular application for which supported Au catalysts may find a niche market is in fuel cells [4, 50] and in particular in polymer electrolyte fuel cells (PEFC), which are used in residential electric power and electric vehicles and operate at about 353-473 K. Polymer electrolyte fuel cells are usually operated by hydrogen produced from methane or methanol by steam reforming followed by water-gas shift reaction. Residual CO (about 1 vol.%) in the reformer output after the shift reaction poisons the Pt anode at a relatively low PEFC operating temperature. To solve this problem, the anode of the fuel cell should be improved to become more CO tolerant (Pt-Ru alloying) and secondly catalytic systems should be developed that can remove even trace amounts of CO from H2 in the presence of excess C02 and water. 

Proton exchange membranes (PEM) fuel cells (or polymer electrolyte fuel cells - PEFCs), with H -conducting polymeric membranes, transports hydrogen (fuel) cations, generated at the anode, to an ambient air exposed cathode, where they are electro-oxidised to water at low temperatures. 

Figure 3.16. Schematic representation of the correlation between polarization resistances (anode, cathode, and cell) and polarization curves [23], (With kind permission from Springer Science+Business Media Journal of Applied Electrochemistry, Characterization of membrane electrode assembhes in polymer electrolyte fuel cells using a.c. impedance spectroscopy, 32(8), 2002, 859-63, Wagner N. Figure 6.)...

Figure 6.42. Picture of the anode configuration for the fourth-generation segmented cell designed by LANL [43], (Reprinted from Journal of Power Sources, 123(2), Bender G, Wilson MS, Zawodzinski TA. Further refinements in the segmented cell approach to diagnosing performance in polymer electrolyte fuel cells, 163-71, 2003, with permission from Elsevier and the authors.)...

Fig. 52. Variation of methanol permeation rate in a polymer electrolyte fuel cell at elevated temperature with cell current density for different methanol feed concentrations. The results show that, for methanol concentrations under 1 m, methanol is effectively consumed at the anode, thus minimizing the permeation rate [117], (Reprinted by permission of the Electrochemical Society).

Okada, T. Theory for water management in membranes for polymer electrolyte fuel cells part 1. The effect of impurity ions at the anode side on the membrane performances. J. Electro-anal. Chem. 1999, 465 (1), 1-17. 

The PEMFC is also referred to as a polymer electrolyte fuel cell or solid polymer electrolyte fuel cell. A schematic drawing ofa single PEMFC is shown in Figure 10.1. In this system, hydrogen fuel supplied to the anode reacts electrochemically atthe electrode... 

Polymer electrolyte fuel cells, also sometimes called SPEFC (solid polymer electrolyte fuel cells) or PEMFC (polymer electrolyte membrane fuel cell) use a proton exchange membrane as the electrolyte. PEEC are low-temperature fuel cells, generally operating between 40 and 90 °C and therefore need noble metal electrocatalysts (platinum or platinum alloys on anode and cathode). Characteristics of PEEC are the high power density and fast dynamics. A prominent application area is therefore the power train of automobiles, where quick start-up is required. 

Instrumentation. The interface within a suitably constructed electrochemical cell to be investigated is placed in the sample position of a standard DRIFT accessory for an infrared spectrometer for a typical design, see [328,329]. Examples reported so far deal with solid polymer electrolyte fuel cells where the surface of the anode layer exposed to a mixed gas atmosphere containing both water and methanol is separated from the environment via a Cap2 window [331, 332]. Various oxidized species and penetrating methanol were observed. 

The basic design of a fuel cell, an ionically conducting electrolyte and separator layer sandwiched between two electronically conducting gas diffusion electrodes (the fuel anode and the oxidant cathode, respectively), is shown schematically in Fig. 2 for a polymer electrolyte fuel cell with an acidic electrolyte and hydrogen and oxygen as the corresponding reactants. Typically, under open circuit conditions, H2/air fuel cells exhibit a cell voltage of... 

The three components of the fuel cell, anode, cathode, and electrolyte form a membrane-electrolyte assembly, as, by analogy with polymer electrolyte fuel cells, one may regard the thin layer of solid electrolyte as a membrane. Any one of the three membrane-electrode assembly components can be selected as the entire fuel cell s support and made relatively thick (up to 2 mm) in order to provide mechanical stability. The other two components are then applied to this support in a different way as thin layers (tenths of a millimeter). Accordingly, one has anode-supported, electrolyte-supported, and cathode-supported fuel cells. Sometimes though an independent metal or ceramic substrate is used to which, then, the three functional layers are applied. 

Planar solid oxide fuel cells are built analogously to other kinds of fuel cells, such as polymer electrolyte fuel cells. Usually, one of the electrodes (the fuel anode or the oxygen cathode) serves as support for the membrane-electrode assembly. To this end, it is relatively thick (up to 2 mm), and thin layers of the electrolyte and... 

Proton exchange membrane fuel cells, also called polymer electrolyte fuel cell or solid polymer electrolyte fuel cells, use a proton exchange membrane, which acts as a solid electrolyte between the anode and cathode electrodes. Proton exchange membrane fuel cells are favored for use in automobiles, residential power as well as in portable devices such as laptops and cell phones. These fuel cells utilize hydrogen gas and air or oxygen to produce power. 

Platinum-Based Anode Catalysts for Polymer Electrolyte Euel Cells Platinum-Based Cathode Catalysts for Polymer Electrolyte Fuel Cells... 

Watanabe M, Zhu Y, Igarashi H, Uchida H (2000) Mechanism of CO tolerance at Pt-alloy anode catalysts for polymer electrolyte fuel cells. Electrochemistry 3 244-251... 

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