Part 2—Impacts of Electrolyte and Reactant Size on Structure Sensitivity in Electrocatalysis: A Geometric Approach

Abstract

In previous work performed by the current authors, an in-depth analysis of the current theories relating particle size to electrocatalytic activity was undertaken. In that work, electronic structure effects, geometry and crystallographic orientation effects, territory theory and support structure effects could not account for the structure sensitivity exhibited in the experimental data. This study builds on that previous work and investigates the impact of electrolyte conditions and reactant size on the structure sensitivity of Au nanocatalysts for multiple electrochemical systems. The Fe3+/Fe2+ reaction was studied for multiple reactant sizes in a wide range of electrolyte conditions. There was a clear impact of reactant size on the critical size at which deviation from bulk electrocatalytic performance takes place. These findings were used to develop a geometric model, which could account for the increase in electrocatalytic activity observed below critical nanoparticle diameters.