Temperature, effect alkaline fuel cells

Fuel cells can be broadly classified into two types high temperature fuel cells such as molten carbonate fuel cells (MCFCs) and solid oxide polymer fuel cells (SOFCs), which operate at temperatures above 923 K and low temperature fuel cells such as proton exchange membrane fuel cells (PEMs), alkaline fuel cells (AFCs) and phosphoric acid fuel cells (PAFCs), which operate at temperatures lower than 523 K. Because of their higher operating temperatures, MCFCs and SOFCs have a high tolerance for commonly encountered impurities such as CO and CO2 (CO c)- However, the high temperatures also impose problems in their maintenance and operation and thus, increase the difficulty in their effective utilization in vehicular and small-scale applications. Hence, a major part of the research has been directed towards low temperature fuel cells. The low temperature fuel cells unfortunately, have a very low tolerance for impurities such as CO , PAFCs can tolerate up to 2% CO, PEMs only a few ppm, whereas the AFCs have a stringent (ppm level) CO2 tolerance. 

Platinum and Pt-based materials are currently the best electrocatalysts for these reactions. The price and the hmited reserves of Pt are the prime obstacles to adequately developing this major field. Extensive research efforts have been devoted to the development of highly active and cost-effective electrocatalysts. This chapter describes recent advances in electrocatalysts for anodic reactions in low-temperature fuel cells that use methanol and ethanol as fuels in acidic media. Special attention is focused on the effort to decrease Pt content in the catalysts. Electrocatalysts employed in alkaline fuel cells are not discussed as they have been adequately covered in Chap. 5. 

Datta J, Dutta A, Mukherjee S (2011) The beneficial role of the Cometals Pd and Au in the carbon-supported PtPdAu catalyst toward promoting ethanol oxidation kinetics in alkaline fuel cells temperature effect and reaction mechanism. J Phys Chem C 115(31) 15324—15334... 

The high-cost of materials and efficiency limitations that chemical fuel cells currently have is a topic of primaiy concern. For a fuel cell to be effective, strong acidic or alkaline solutions, high temperatures and pressures are needed. Most fuel cells use platinum as catalyst, which is expensive, limited in availability, and easily poisoned by carbon monoxide (CO), a by-product of many hydrogen production reactions in the fuel cell anode chamber. In proton exchange membrane (PEM) fuel cells, the type of fuel used dictates the appropriate type of catalyst needed. Within this context, tolerance to CO is an important issue. It has been shown that the PEM fuel cell performance drops significantly with a CO con-... 

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