The influence of surface crystallography on electro-oxidation of trivalent chromium at Au(2 1 0) and Au(3 1 1) electrodes

The electrochemical oxidation of Cr(III) to Cr(VI) species was investigated by cyclic voltammetry, differential capacity and current-transient measurements on the stepped (2 1 0) and (3 1 1) faces of gold. The process was found to be structure sensitive. Moreover, the Au(3 1 1) electrode appears to be more active than Au(2 1 0). The differences between the activities of the electrode have been attributed mainly to the different adsorbability of OH− anions on both electrodes but also to the blocking effect of the strongly adsorbed CrO 2 - anions.