Modeling the triple-path electro-oxidation of formic acid on platinum: Cyclic voltammetry and oscillations

Abstract

A renewed electrochemical model for the oscillatory electro-oxidation of formic acid on platinum in acidic medium is presented. The model includes recently reported mechanistic findings and evaluates three reaction pathways towards the production of CO2. Two of these processes consist of dehydrogenation and dehydration of the formic acid with adsorbed formate species as common intermediate. The third and most active pathway includes a fast oxidation of the formate ion. The proposed mechanism is translated into a kinetic model and tested in numerical simulations under voltammetric and oscillatory regimes. Numerical results are further compared with experimental ones. A successful adjustment of the oscillatory characteristics, namely frequency and amplitude of the oscillations suggest a good approximation to the actual mechanism of the oxidation of formic acid on platinum. The role of electrochemical oscillations in mechanistic studies is discussed and a comparison with previous models is also provided. Finally, some perspectives are suggested.