The reactivity and selectivity of CO2 reduction has been examined at gas-diffusion electrodes made of Ru, Pd and their alloy (Ru:Pd = 1:1). It was found that the current efficiency for the formation of formic acid at the gas-diffusion electrodes with Ru-Pd catalysts is 90% at -1.1 V vs. NHE, where the current density is 80 mA.cm(-2). In addition, no CO formation was observed at gas-diffusion electrodes with Ru-Pd catalysts.