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, E-p, and T is linear, the slope being -4.64 x 10(-4) V K-1. The variation of E-p with T allows one to determine the entropy of the process, DeltaS, 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 adsorption on the Pt(110) substrate. The temperature modification does not alter the Pt(110) surface which retains the (1 x 1) structure. The overall adsorption 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 cm(-2). (C) 2001 Elsevier Science B.V. All rights reserved.