Multiscale modelling unveils how mesoscopic mass transport determines the electrocatalytic activity

Abstract

We develop a multiscale model that combines density functional theory, microkinetic simulation, and mass-transport modeling to link microscopic mechanisms of the oxygen reduction reaction (ORR) to macroscopic electrocatalytic performance. By resolving potential-dependent surface concentrations of H⁺, OH⁻, and O₂ at Pt electrodes, the model captures local pH effects and accurately describes the influence of active site density on the ORR half-wave potential. Our model successfully reproduces experimental measurements and highlights the role of mesoscopic mass transport in predicting the electrocatalytic activity.