Deconvoluting Cyclic Voltammograms To Accurately Calculate Pt Electrochemically Active Surface Area

Abstract

An accurate measure of the electrochemically active surface area (ECSA) of an electrode is necessary to quantify electrocatalytic activity. Herein, we develop a method to deconvolute experimental cyclic voltammograms measured on platinum electrodes which predominately contain 111 terraces with 110 and 100 steps. We define simple functions that can be fit to experimental data to represent various contributions to the total voltammogram, including hydrogen adsorption on 111 terraces and competitive hydrogen and hydroxide adsorption on 110 and on 100 steps. We use our prior density functional theory insight to accurately calculate the ECSA and the proportion of 111, 100, and 110 sites. We validate this method for experimental cyclic voltammograms measured on single-crystal stepped platinum surfaces (with 111 terraces), where the surface area is known, then extend to polycrystalline and nanoparticle platinum electrodes.