Electrocatalysis of carbon black- or activated carbon nanotubes-supported Pd–Ag towards methanol oxidation in alkaline media

Carbon black supported bimetallic palladium–silver (Pd–Ag/C) catalysts with different Ag loadings were prepared by borohydride reduction of mixed metal salts and carbon support. Electrochemical activities of these catalysts towards methanol oxidation in alkaline media were examined and the Pd–Ag(1:1)/C catalyst (onset potential of −0.59 V) shows better catalytic activity than the Pd/C catalyst (onset potential of −0.49 V). The addition of Ag also facilitates methanol oxidation and removal of the adsorbed CO. The synthesized activated carbon nanotubes (CNTs)-supported Pd–Ag(1:1) catalyst exhibits even better catalytic activity contributed from larger electroactive surface area and better intrinsic catalytic activity than the carbon black supported bimetallic palladium–silver (Pd–Ag/C) catalyst.