Influence of the surface morphology of smooth platinum electrodes for the sodium borohydride oxidation reaction.

P.Y. Olu (1) , B. Gilles (2) , N. Job (3) , M. Chatenet (1)

1 LEPMI - Laboratoire d'Electrochimie et de Physico-chimie des Matériaux et des Interfaces
2 SIMaP - Science et Ingénierie des Matériaux et Procédés
3 Institut Chimie Lab. Génie Chimique

In this study, we show that the platinum electrode preparation procedure influences its behavior towards the borohydride electrooxidation reaction (BOR) mechanism. Cycling a smooth polycrystalline Pt electrode in alkaline electrolyte within the water stability domain prior to the BOR characterization radically changes the shape of the BOR voltammogram obtained in hydrodynamic conditions using the rotating disk electrode (RDE) setup, compared to the "classical" one measured on a smooth polycrystalline Pt electrode just polished before the BORRDE study. This particular BOR voltammogram is reversibly brought back to the "classical" one after voltammetric cycling in borohydride alkaline media. These changes in the BOR voltammogram highlight the sensitivity of the BOR mechanism towards the Pt surface morphology. A first comparison of the Pt electrode surface before and after the voltammetric cycling in alkaline media using tapping mode atomic force microscopy (AFM) shows no morphological differences between the two surfaces within the AFM observation range, suggesting a very fine atomic structure disordering of the Pt surface. Such strong dependence of the BOR mechanism on Pt regarding the electrode atomic structuring opens the way to future studies focusing on the BOR on well-defined Pt single crystals. (C) 2014 Elsevier B.V. All rights reserved.

Domaines: Matériaux

P.Y. Olu, B. Gilles, N. Job, M. Chatenet. Influence of the surface morphology of smooth platinum electrodes for the sodium borohydride oxidation reaction.. Electrochemistry Communications, 2014, 43, pp.47-50. ⟨10.1016/j.elecom.2014.02.018⟩. ⟨hal-01071859⟩