Electro-Oxidation of Methanol and Ethanol on Poly(3,4-Ethylenedioxythiophene) with Dispersed Pt, Pt plus Sn, and Pt plus Pb Particles

The influence of tin and lead additives on the catalytic activity of platinum particles dispersed on a poly(3,4-dioxyethylenethiophene) (PEDT) layer deposited on gold or steel towards anodic oxidation of methanol and ethanol was studied. It was found that these additives increase the rate of anodic oxidation of both alcohols. It was also found that the electro-catalytic properties of PEDT depend on the kind of support used for its deposition. The authors have shown that these additives (Pb and Sn) increase the rate of anodic oxidation of both alcohols on platinum deposited on PEDT, but tin was evidently more elective than lead. In the presence of Sn, the steady-state current density of methanol oxidation increases about 100 times while Pb only promotes the platinum catalyst activity by about 2 times. In the authors opinion the most probable mechanism for the tin promotion effect seems to be a homogenous catalytic reaction with the participation of the Sn (IV) and Sn (TT) ions as mediators.