The temperature dependence of the cyclic-voltammetry response for the Pt(110) electrode in aqueous H2SO4 solution

The under-potential deposition of H (upd H) and anion adsorption on Pt(110) in 0.5 M aqueous H2SO4 solution is investigated by application of cyclic-voltammetry (CV). The data show that an increase in T results in a shift of the CV peak towards less positive potentials and changes in its morphology; the peak current is not affected by T. The relation between the peak potential, Ep, and T is linear, the slope being −4.64×10−4 V K−1. The variation of Ep with T allows one to determine the entropy of the process, ΔS, that is −44.8 J mol−1 K−1. Comparison of this value with ΔS for Hupd adsorption on Pt(111) suggests that the sharp peak represents Hupd adsorption on the Pt(110) substrate. The temperature modification does not alter the Pt(110) surface which retains the (1×1) structure. The overall adsorption charge density does not vary upon T variation (for 273≤T≤333 K) and its average value is 213 μC cm−2.