Theoretical Modeling of Electrochemical Proton-Coupled Electron Transfer

Proton-coupled electron transfer (PCET) plays an essential role in a wide range of electrocatalytic processes. A vast array of theoretical and computational methods PT have been developed to study electrochemical PCET. These methods can be used to calculate redox potentials and pK, values for molecular electrocatalysts, proton-coupled redox potentials and bond dissociation free energies for PCET at metal and semiconductor interfaces, and reorganization energies associated with electrochemical PCET. Periodic density functional theory can also be used to compute PCET activation energies and PT perform molecular dynamics simulations of electrochemical interfaces. Various approaches for maintaining a constant electrode potential in electronic structure calculations and modeling complex interactions in the electric double layer (EDL) have been developed. Theoretical formulations for both homogeneous and heterogeneous electrochemical PCET spanning the adiabatic, nonadiabatic, and solvent-controlled regimes have been developed and provide analytical expressions for the rate constants and current densities as functions of applied potential. The quantum mechanical treatment of the proton and inclusion of excited vibronic states have been shown to be critical for describing experimental data, such as Tafel slopes and potential-dependent kinetic isotope effects. The calculated rate constants can be used as input to microkinetic models and voltammogram simulations to elucidate complex electrocatalytic processes.

Automated summary

Proton-coupled electron transfer (PCET) is crucial in electrocatalytic processes. Various theoretical and computational methods have been developed to study electrochemical PCET and calculate related potentials and energies. Periodic density functional theory is also utilized to perform molecular dynamics simulations. Maintaining a constant electrode potential and modeling complex interactions in the electric double layer have been explored. Both homogeneous and heterogeneous electrochemical PCET have been studied, providing analytical expressions for rate constants and current densities.