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-v oltammetry (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 poten tial, E-p, and T is linear, the slope being -4.64 x 10(-4) V K-1. The varia tion of E-p with T allows one to determine the entropy of the process, Delt aS, that is -44.8 J mol(-1) K-1. Comparison of this value with DeltaS for H -upd adsorption on Pt(111) suggests that the sharp peak represents Hupd ads orption on the Pt(110) substrate. The temperature modification does not alt er the Pt(110) surface which retains the (1 x 1) structure. The overall ads orption charge density does not vary upon T variation (for 273 less than or equal to T less than or equal to 333 K) and its average value is 213 muC c m(-2). (C) 2001 Elsevier Science B.V. All rights reserved.