Spectroelectrochemical Evaluation of Rh Microparticles as Electrocatalyst for Carbon Monoxide and Formic Acid Oxidation

Electrooxidation of carbon monoxide and formic acid was performed on Rh microparticles deposited on both, Glassy Carbon (Rh/GC) and polyaniline films (Rh/PANI), to evaluate the electrocatalytic activity of those electrodes. The deposit of Rh microparticles on those substrates provides a higher surface and exhibits a better electrocatalytic activity compared with that shown by smooth Rh for the electrochemical oxidation of formic acid in sulphuric acid. The oxidation of CO and HCOOH on Rh/GC and Rh/PANI was followed using in situ Multi-Step FTIR Spectroscopy (MS-FTIRS). Either linear or bridge bonded adsorbed CO (COl, COb), has been observed by FTIRS as the main species. In comparison to the adsorption of CO on smooth Rh surface, the IR features of CO adsorbed on Rh/GC and Rh/PANI electrodes showed an anomalous behaviour.