HALIDE CATALYSIS OF THE ELECTROCHEMICAL OXIDATION OF GOLD IN ACETONITRILE

The anodic oxidation of metallic gold in acetonitrile, which is normal ly inhibited by traces of water causing passivation, can be promoted b y halide catalysis. The deblocking mechanism is based on displacement of water by concurrent adsorption of halide ions. Only small quantitie s of halide, enough to cover the anode surface with a monoionic layer, are required for the process. The catalytic effect increases in the o rder Cl- < Br- << I-. The effect can be used for the easy preparation of Au+ solutions.