ELECTROCHEMICAL REDUCTION OF CARBON-DIOXIDE ON HYDROGEN-STORING MATERIALS .1. THE EFFECT OF HYDROGEN ABSORPTION ON THE ELECTROCHEMICAL-BEHAVIOR ON PALLADIUM ELECTRODES

Pd was used as an electrode for the electrochemical reduction of CO2 in aqueous KHCO3 solution to investigate the effect of the absorption of hydrogen on electrochemical behavior. The current efficiencies for CO and HCOOH production increased after hydrogen was absorbed into the Pd electrode. This increase was a result of the increase in the selectivity for CO2 reduction resulting from the suppression of H-2 evolution and/or the increase of the actual reaction rates of CO and HCOOH production. The participation of absorbed hydrogen in the reduction of CO2 is suggested, and the possibility of direct attack on the reaction intermediates by absorbed hydrogen is discussed.