Decoupling electron transfer defines a quantitative kinetic framework for oxygen evolution catalysis

Abstract

Abstract The oxygen evolution reaction underpins many energy conversion technologies, yet its performance is fundamentally constrained by sluggish reaction kinetics at catalyst surfaces. Current catalyst design remains largely empirical because most strategies correlate bulk structural descriptors with overall activity rather than resolving the intrinsic kinetics of elementary reaction steps. Here, we show that open-circuit voltage–pulse voltammetry can quantitatively determine the * OOH formation rate, a rate-determining step in oxygen evolution. Unlike conventional electrochemical techniques, this method isolates * OOH formation-related electron transfer by interrupting electron transfer from electrocatalyst to external circuit while sustaining electron supply from hydroxide ions. Coupling this descriptor with a pulse voltammetry method for quantifying * OH deprotonation kinetics yields a unified, step-resolved kinetic framework that reveals how different dopants selectively accelerate either * OOH formation or * OH deprotonation. Fe primarily facilitates * OOH formation, whereas Mn selectively promotes * OH deprotonation. Guided by these insights, a rationally designed NiFeMn catalyst concurrently enhances both processes, delivering improved oxygen evolution performance. This methodology provides a practical means to quantify elementary reaction kinetics and accelerate the discovery of high-performance electrocatalysts.