Abstract: In the present paper, possibility to realize the double purposes of both catalytic oxidation of ethene to useful organic products and concurrent production of hydrogen fuel by means of photoelectrochemical method was investigated, as well as the functions of the metallic films (Au, Ag and Pd plated on the surface of n-GaP semiconductor electrode) in preventing photocorrosion of the electrodes and in catalytic oxidation of ethene.The effects of such factors, as applied bias, pH, solvent, and so on, on the anodic reactions have been studied.Possible mechanisms of the reactions have been tentatively discussed.