Nonplatinum Catalysts for Fuel Cell Anodes

For the electrooxidation of alcohols in alkaline medium (see Section 6.4), Shen et al. (2006) suggested a platinum or palladium catalyst promoted with 25 wt% of nickel oxide NiO deposited on a carbon-black support. According to then-data, this additive substantially accelerates the electrooxidation of methanol in an alkaline medium. Tarasevich et al. (2005) suggested a Ru-Ni catalyst deposited on carbon black for the electrooxidation of ethanol in an alkaline medium it is considerably more active than pure ruthenium. Under the operating conditions of fuel cells in acidic media as well as in contact with proton-conducting membranes of the Nafion type, the use of nonplatinum catalysts is highly restricted, owing to corrosion problems. 

It has been known for a long time that tungsten carbide (WC) is a good catalyst for hydrogen oxidation in acidic solutions. In contrast to platinum, tungsten carbide remains active even in CO-containing hydrogen (McIntyre et al., 2002). A practical use of this material is made difficult by the fact that an accidental shift of potential in the positive direction causes its surface to become oxidized (much more so than the surface of disperse nickel) and to lose its catalytic activity. 

A special case of electrocatalysis is encountered in the enzyme and bacterial biofuel cells discussed in Section 9.2, where very restrictive conditions are imposed on the function of biocatalysts a pH value of the medium of about 7 and a temperature close to room temperature. 

An interesting piece of work was reported by Mondal et al. (2005), who deposited a film of polyaniline (about 35 mg/cm ) by electrochemical means on an electrode of stainless steel. This electrode proved to be active for the 

In a recent review paper by Shao (2011) the author mentions that because of limited resources and high cost, platinum electrocatalysts, used in many low-temperature fuel cells, hinder the commercialization of fuel cell power plants. Recent efforts have focused on the discovery of palladium-based electrocatalysts with no or little platinum. The paper overviews progress in electrocatalysis by palladium-based materials for the reaction of hydrogen oxidation as well for the reaction of oxygen reduction (see the next section). 

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