Influence of Underpotential Deposition of Copper with Submonolayer Coverage on Hydrogen Adsorption at the Stepped Surfaces Pt(955), Pt(322) and Pt(544) in Sulfuric Acid Solution

C. Nishihara and H. Nozoye [J. Electroanal. Chem., Vol.396, pp.139-142, 1995]

Effects of the coverage of underpotentially deposited copper submonolayer on hydrogen adsorption were examined for the three stepped surfaces; Pt(955), Pt(322) and Pt(544) of single crystals. A very small amount of copper preferentially blocks hydrogen adsorption to the (100) step sites as shown for (322) surface qualitatively in Fig.1. The fact supports our previous conclusion (J. Electoanal. Chem., 386(1995) 75) that the most positive peak of copper-UPD relates to the deposition of copper to (100) step sites of these three surfaces.

Fig. 1. Cyclic voltammogram of the Pt(322) surface between 0.06 V and 0.08 V starting from 0.06 V in 0.5 M H₂SO₄ solution at 20 mV/s. The surface was previously covered with one monolayer of copper. The inset shows the cyclic voltammogram of the clean surface in 0.5 M H₂SO₄ at 20 mV/s.