Electrocatalysis for the Direct Alcohol Fuel Cell - Fuel Cell Catalysis: A Surface Science Approach - page 362

been shown that both doped and undoped manganese oxides [Chatenet et al., 2006]
display good activity and selectivity with regard to a four-electron reduction process,
and therefore could be used as cathode catalysts in SAMFCs. In alkaline media, MN 4
catalysts such as porphyrins and phthalocyanines display higher activity with regard to
ORR and higher selectivity with regard to water production than in acidic media.
Moreover, in such systems, crossover of fuel is limited owing to the transfer of
hydroxyl ions from the cathode side to the anode side by electro-osmosis. For the oxi-
dation reaction of alcohol in this system, Pt-based anodes are mainly used [Matsuoka
et al., 2005; Varcoe and Slade, 2006; Yu and Scott, 2004; Demarconnay et al., 2007].
Bianchini's group has developed a non-noble Co-based catalyst [Barbaro et al., 2006],
and has claimed that these catalysts are active for ethanol electro-oxidation in an
alkaline medium, and could be used in a DEFC. Finally, in a SAMFC, the use of a
solid polymer as electrolyte [Matsuoka et al., 2005; Varcoe and Slade, 2006; Yu
and Scott, 2004; Demarconnay et al., 2007] instead of KOH gel, which is very corros-
ive, avoids the problem of safety. It also limits the carbonation of the electrolyte by
gaseous impurities or reaction products.

ACKNOWLEDGEMENT

Part of this chapter is based on thesis works by Laetitia Dubau, St ` ve Baranton, and S ´ verine
Rousseau. We also acknowledge Emmanuel Garnier for his helpful contributions to deter-
mining the crystallographic structure of catalysts.

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