SPECIFIC ADSORPTION OF HYDROGEN ON POLYCRYSTALLINE PLATINUM-ELECTRODE

When a polycrystalline Pt electrode was activated by repeating anodic cycles, peak III appeared between peak I and peak II in the anodic-going voltammogram. However, in the cathodic-going voltammogram peak III did not appear at the same potential as anodic peak III. Peak III was observed to increase in height and the potential of peak III was shifted towards the noble potential as the potential sweep rate was increased. It was considered that the adsorption potential of H(III) was in the region of the weakly adsorbed hydrogen, H(w), and it took longer for H(III) to be adsorbed in comparison with H(w). The site which would be adsorbed by a H(w) atom was considered to be adsorbed by two H(III) atoms.