Electrocatalysis from First Principles: Mechanistic Insights into the Oxygen Reduction Reaction

Electrocatalysis is controlled by the elementary reactions that occur at the interface between the electrode and the solution phase along with the electrochemical potential that results across this interface. Elucidating the electrochemical behavior at this interface, however, presents a considerable challenge due to complexity of the surface chemistry, the explicit atomic and molecular structure of the solution phase at the interface, the presence and formation different ions and their specific location in solution or on the surface, and the surface potentials and electric fields that results as a function of the surface reactivity. Professor Andrzej Wieckowski has been one of the leading pioneers in the development and application of in-situ methods to follow the atomic and electronic scale features in electrochemical systems under working conditions and establish fundamental principles that govern surface reactivity in electrochemical and electrocatalytic systems.   His persistent encouragement and nurturing also helped to establish first principle theory and simulation within the electrochemistry community.  While theory has become an invaluable partner together with in-situ experiment, there are still a number of challenges in simulating more realistic materials and interfaces and modeling constant potential systems.  Herein, we present an approach to simulate the elementary pathways and kinetics for constant potential systems and highlight the opportunities and challenges of this approach.  The results are used to construct first principles based kinetic Monte Carlo simulations to model different electrochemical systems.  We discuss the application of the approach to simulate the electrocatalytic reduction of oxygen over transition metal surfaces as well as nitrogen doped carbon-based substrates.