Hydrogenation of ethylene on metal electrodes. Part 4.—Electroreduction of ethylene at a platinum electrode

Abstract

Electroreduction of ethylene was studied at a smooth platinum electrode in aqueous HClO₄ and H₂SO₄ solutions. The reduction proceeds at a much higher rate than the hydrogen evolution reaction (≈ 10³ times faster). Kinetic parameters of the reaction (the Tafel slope, ethylene pressure dependence and solution pH dependence) and the structure of the adsorption layer during the reaction lead to the same conclusion as previously obtained for the reduction by molecular hydrogen at Pt on open circuit; namely that the slowest surface step is C₂H₅(a)+ H(a)→ C₂H₆.