Ezra Clark, Ph.D.

Elucidating the mechanism of cation promotion in electrocatalytic processes

Abstract

Electrocatalysis enables chemical transformations to be directly driven by renewable electricity, providing a viable route toward reducing the environmental impact of the chemical industry. Unfortunately, the energy conversion efficiency of many electrocatalytic processes is insufficient for industrial implementation. The energy conversion efficiency of electrocatalytic processes depends on the properties of the electrochemical active site, which consists of both the electrode surface and the solvated ions in its immediate vicinity. The influence of these ions in modulating the rates of electrocatalytic processes is exemplified by the cation sensitivity of electrochemical CO2 reduction to ethene, which is enhanced by roughly 2 orders of magnitude as the identity of the electrolyte cation moves down the alkali metal group. Many electrocatalytic reactions exhibit similar cation-dependent activity. However, the mechanism of cation promotion remains a mystery. The rate of catalytic turnover is a function of both the steady state coverage of reaction intermediates on the catalyst surface and their surface lifetimes. However, no technique has existed for measuring either of these critical parameters until now. This project aims to directly quantify the impact of cation identity on these critical performance parameters under reaction conditions for the first time. These insights will be leveraged to design electrocatalytic systems with superior energy conversion efficiency, facilitating the commercial implementation of electrocatalytic technologies and easing the environmental burden of the chemical industry.

Award amount: $150,000

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