Kinetics of carbon dioxide adsorption on a platinum electrode

Abstract

Summary The kinetics of CO2 adsorption on a platinized electrode were investigated by radiometric method. It was shown that the CO2 adsorption is due to surface reaction with hydrogen adsorbed on the electrode. The rate of adsorption increases with the electrode potential in the range of 0.05–0.15 V and follows the secondorder reaction. In the range of 0.20–0.25 V the rate of adsorption decreases according to the first-order reaction. The COOH radical is postulated as a product of CO2+Hads reaction. In the range of potentials 0.05–0.20 V the maximum surface concentration of adsorbed species is ca. 9.6×1014 molecules cm−2. The bulk concentration of CO2 and temperature do not influence the surface concentration. The apparent heat of activation of CO2+Hads reaction are 50.0 kJ mol−1 at 0.05 V and 38.5 kJ mol−1 at 0.20 V, respectively.