Study of the Hydrogen Oxidation Reaction on Supported Pt Nanoparticles

M.A. MONTERO; M.R. GENNERO DE CHIALVO; A.C. CHIALVO

Sevilla

Congreso; The 59th Annual Meeting of the International Society of Electrochemistry; 2008

International Society of Electrochemistry (ISE)

Growing interest in using hydrogen as a renewable fuel has enhanced efforts to improve understandings of the electrocatalytic behaviour of Pt electrode for the hydrogen oxidation reaction (hor), the anodic reaction in the low-temperature proton exchange membrane fuel cells. In this sense, a detailed kinetic study of the hor on a smooth Pt electrode was recently carried out [1]. However, in the fuel cell electrodes Pt is finely dispersed on a conducting support. Therefore, a kinetic study on Pt nanoparticles supported on conducting non-porous substrates that allow the evaluation of the intrinsic kinetic parameters should be of interest. On this context, the present work deals with the study of the hor on Pt nanoparticles supported on glassy carbon and on gold. Nanoparticles were synthesized by two different methods. The first method, developed by Aika et al. [2], consisted of a monodisperse Pt sol obtained by the reduction of chloroplatinate ion by sodium citrate. It has been also applied the method proposed by Rampino and Nord [3] where a capping polymer material, in this case sodium polyacrylate, was used to control the shape and size of the colloidal nanoparticles. Platinum ions were reduced in this case by hydrogen gas. Electrodes were prepared through the evaporation of microvolumes of the emulsions on the substrates mentioned above. The kinetic evaluations were carried out potentiostatically on rotating disc electrodes. The experimental dependences of the current density on overpotential were analyzed on the basis of kinetic expressions derived for the Volmer-Heyrovsky-Tafel mechanism [1]. The results show different behaviours with respect to smooth platinum, suggesting the existence of a strong interaction between the nanoparticles and the substrate.   1. P.M. Quaino, M.R. Gennero de Chialvo, A.C. Chialvo, Electrochim. Acta 52 (2007) 7396. 2. K. Aika, L.L. Ban, I. Okura, S. Namba, J. Turkevich, J. Res. Inst. Catal. Hokkaido Univ. 24 (1976) 54.    3. L.D. Rampino, F.F. Nord, J. Amer. Chem. Soc. 63 (1941) 2745.