Boron-doped diamond powder as catalyst support for fuel cell applications

The modification of boron-doped diamond powder with metallic oxides using the sol–gel method to prepare high area and very stable electrodes for the methanol oxidation reaction is reported here. The catalyst clusters thus prepared are irregularly distributed on the BDD powder surface having sizes varying between 500 nm and 5 μm and formed by the agglomeration of many nanoparticles. Electrochemical studies in acid media demonstrate that the deposited particles have a good electrical contact with the diamond powder surface and high purity. Moreover, the use of the sol–gel method on a BDD powder substrate leads to the formation of metallic and metallic oxides deposits of the desired composition. The electrocatalyst composite prepared in this manner (Pt–RuOx/BDD powder) shows an excellent activity for methanol oxidation presenting an onset potential 20 mV lower than that observed on a Pt–Ru/C commercial catalyst, probably due to the ruthenium oxide contribution to the overall catalytic activity.