THE TEMPERATURE-DEPENDENCE OF HYDROGEN AND ANION ADSORPTION AT A PT(100) ELECTRODE IN AQUEOUS H2SO4 SOLUTION

Research on the underpotential deposition of H (upd H) and anion adsor ption on Pt(100) in 0.5 M aqueous H2SO4 solution by cyclic voltammetry (CV) indicates that the overall adsorption/desorption charge density is affected strongly by variation of the temperature T, and that it de creases by about 1/3 when T is raised from 293 to 328 K. The sharp pea k at 0.375 V vs. RHE assigned to the anion adsorption decreases its po tential, current density and charge density. The CV feature assigned t o the upd H, a wide shoulder overlapping the sharp peak, also decrease s with T augmentation, but the decline of its charge density is less p ronounced. The results indicate that the H-apd and anion surface cover ages, theta(Hapd) and theta(AN) respectively are strongly temperature- dependent. This behavior may be assigned to lateral repulsive interact ions.