Irradiation of a polycrystalline silver electrode with near-u.v./visible light in solutions containing either dissolved carbon dioxide or nitrate ions produces strong enhancement of the cathodic current. Maximum photocurrent efficiency is observed for the photon energies of about 3.5 eV characteristic of surface plasmons on silver. In the presence of carbon dioxide in solution, the electrode illumination not only increases the rate of CO2 to CO reduction but also shifts the onset of the CO production by about 0.5 V to less cathodic potentials.