Dynamic Electrocatalysis Enhances the Oxygen Evolution Reaction Activity of Iridium Oxides

Scalable green hydrogen production by proton exchange membrane electrolysis necessitates more materials‐ and energy‐efficient processes, with improvements to catalysis of the oxygen evolution reaction (OER) offering the greatest impact. We demonstrate that dynamically operating iridium oxide anodes, employing square‐wave potentials, with optimized parameters enhances the OER activity under acidic conditions by up to 480%. Combining time‐resolved operando NEXAFS and DFT‐informed microkinetic modeling, the enhancement is attributed to increased surface deprotonation and a decoupled reaction mechanism. Specifically, the coverage of deprotonated species is boosted by potential modulation, accelerating the reaction kinetics by reducing energetic barriers and providing proton‐acceptor sites neighboring the active site. Decoupling enables the conversion of previously adsorbed water to oxidized intermediates at a high potential. A subsequent low potential segment allows efficient transformation of the oxidized intermediates to O 2 , followed by repopulation with adsorbed water. This mechanism is facilitated by the applied potential and the degree of surface deprotonation simultaneously and dynamically modulating the free energy landscape, which switches the rate‐determining step. Dynamic electrocatalysis, proven here as advantageous for the OER, generally offers a route for boosting the product turnover per catalytically active atom beyond the limits of static catalyst design strategies.