PERCHLORATE ADSORPTION ON POLYCRYSTALLINE GOLD ELECTRODES IN AQUEOUS PERCHLORIC-ACID

Cyclic voltammetry was performed with polycrystalline gold electrodes in aqueous perchloric acid electrolytes in the concentration range 10(-3) M HClO4 to HClO4.5.5 H2O (approx. 7 M). In the so-called double layer region the diffuse layer capacity minimum was identified from the current minimum. The resulting potential of zero charge, U(pzc), (vs. SHE and corrected for the liquid junction potential) does not change systematically with the perchloric acid concentration. The onset of oxygen adsorption at high potentials, U1/2, is constant vs. RHE in the whole concentration range investigated. The results indicate that the interaction of perchlorate with polycrystalline gold is weak at potentials between U(pzc) and the oxygen adsorption potential U1/2.