Interpreting Tafel Behavior of Consecutive Electrochemical Reactions through Combined Thermodynamic and Steady State Microkinetic Approaches

Authors
J. Tyler Mefford,
Zhenghang Zhao,
Michal Bajdich,
William C. Chueh
Year of publication
2020
Journal
Energy & Environmental Science
Volume
13
Starting page
622
Ending page
634
Assessing the reaction pathway of multi-electron-transfer reactions is an essential yet difficult task for the rational design of electrocatalysts. In this work, we develop a heuristic approach that combines thermodynamic adsorption energetics calculated through density functional theory with microkinetic modeling using the steady state approximation to interpret the potential-dependent Tafel behavior of consecutive electrochemical reactions. In doing so, we introduce a kinetic framework for ab initio calculations that ensures self-consistent adsorption energetics based on kinetically limited adsorbate coverages. The approach is applied to experimental results on CoOx(OH)2-x single crystal electrocatalyst particles yielding coverage dependent mechanistic information and identification of the rate-limiting step with standard rate constants for the oxygen evolution reaction on the (11-20) surfaces of the β-Co(OH)2, β-CoOOH, and CoO2 bulk phases. This generalizable method enables catalyst benchmarking based on determining the active species involved and associated intrinsic reaction rate constants in consecutive multi-electron-transfer reactions. Computational data available at https://www.catalysis-hub.org/publications/MeffordInterpreting2019.
Funding sources