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

Abstract The under-potential deposition of H (upd H) and anion adsorption on Pt(110) in 0.5 M aqueous H 2 SO 4 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, E p , and T is linear, the slope being −4.64×10 −4 V K −1 . The variation of E p with T allows one to determine the entropy of the process, Δ S , that is −44.8 J mol −1 K −1 . Comparison of this value with Δ S for H upd adsorption on Pt(111) suggests that the sharp peak represents H upd 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 .