Oxophilic Sites Mediated Dynamic Oxygen Replenishment to Stabilize Lattice Oxygen Catalysis in Acidic Water Oxidation

Abstract

Developing efficient and durable catalysts for the oxygen evolution reaction (OER) in acidic media is essential for advancing proton exchange membrane water electrolysis (PEMWE). However, catalyst instability caused by lattice oxygen (O_L) depletion and metal dissolution remains a critical barrier. Here, we propose an oxophilic-site-mediated dynamic oxygen replenishment mechanism (DORM), in which O_L actively participates in O–O bond formation and is continuously refilled by water-derived species. Oxophilic dopants modulate the local electronic structure, lower the energy barrier for oxygen vacancy healing, and reorganize the interfacial hydrogen-bond network to enhance water mobility, orientation, and proton accessibility, collectively promoting water dissociation and stabilizing O_L catalysis. The optimized catalyst achieves a low overpotential of 289 mV and exceptional durability, operating continuously for 650 h at 10 mA cm^–2 in acidic electrolyte and maintaining stable performance for 280 h at 1 A cm^–2 in a PEMWE. This work establishes a mechanistic framework for dynamic O_L redox and provides a rational strategy for designing robust, noble-metal-free acidic OER electrocatalysts.