Methanol oxidation on Pt, PtRu, and colloidal Pt electrocatalysts: a DEMS study of product formation

Current efficiencies of CO2 during methanol oxidation were determined by di fferential electrochemical mass spectrometry (DEMS). The influences of meth anol concentration, electrode structure and ruthenium on methanol oxidation have been investigated. CO2 is formed via COad, oxidation in a serial reac tion, while dissolved intermediates, i.e. formaldehyde and formic acid are also formed in a parallel reaction. The chance that these intermediates can further be oxidised depends on the diffusion and convection conditions in connection with the surface structure of the Pt electrode. High methanol co ncentrations favour the reaction path via dissolved intermediates. Ru promo tes methanol oxidation to CO2 via COad, leading to a higher current efficie ncy of CO2. (C) 2001 Elsevier Science B.V. All rights reserved.