Co-adsorption of cations causes the apparent pH dependence of hydrogen adsorption on a stepped platinum single-crystal electrode

Published

October 23, 2017

Author(s)

Xiaoting Chen, Ian McCrum, Kathleen Schwarz, Michael Janik, Marc Koper

Abstract

The successful deployment of advanced energy-conversion systems depends critically on our understanding of the fundamental interactions of the key intermediates (hydrogen and hydroxyl) at electrified metal-aqueous electrolyte interfaces. Herein, the effect of alkali metal cations (Li+, Na+, K+ and Cs+) on the non-Nernstian pH shift of the step-related voltammetric peak of the Pt(553) electrode is investigated over a wide pH window (113) by means of experimental and computational methods. Our results show that the co-adsorbed alkali cations along the step weaken the OH adsorption at the step sites, causing a positive shift of the potential of the step- related peak on Pt(553). Density functional theory calculations explain our observations on the identity and concentration of alkali cations on the non-Nernstian pH shift, and provide definite proof that cation-hydroxyl co-adsorption causes the apparent pH dependence of "hydrogen" adsorption in the step sites of platinum electrodes.

Citation

Angewandte Chemie-International Edition

Pub Type

Journals

Keywords

platinum, electrochemistry

Citation

Chen, X. , McCrum, I. , Schwarz, K. , Janik, M. and Koper, M. (2017), Co-adsorption of cations causes the apparent pH dependence of hydrogen adsorption on a stepped platinum single-crystal electrode, Angewandte Chemie-International Edition (Accessed October 8, 2025)