Metal Oxides Dispersed on Vulcan XC-72 as Electrocatalysts for the Oxygen Reduction Reaction in Aqueous Acidic Electrolyte

摘要

The performance of direct methanol fuel cells (DMFC) is strongly hampered by the poor kinetics of both the methanol oxidation reaction (MOR) and the oxygen reduction reaction (ORR). In addition to the kinetic issues, the DMFC cathodes are also depolarised by methanol that is permeating through state-of-the-art polymer electrolytes. To overcome this problem a quite expensive membrane technology is needed. An alternative would be to use an oxygen reduction electrode, which is not depolarised by methanol. Our studies concentrate on the oxygen reduction activity of perovskites and pyrochlores. We are investigating the relationship between the oxide structure and the ORR activity including the methanol tolerance in acid solution. The study of the oxide catalysts aims at gaining a general view on the electrocatalytic behaviour towards the ORR in order to select the best materials for more detailed and defined studies.