Bias-Induced Ga-O-Ir Interface Breaks the Limits of Adsorption-Energy Scaling Relationships for High-Performing Proton Exchange Membrane Electrolyzers.

Rationally manipulating the in-situ formed catalytically active surface of catalysts remains a significant challenge for achieving highly efficient water electrolysis. Herein, we present a bias-induced activation strategy to modulate in-situ Ga leaching and trigger the dynamic surface restructuring of lamellar Ir@Ga2O3 for the electrochemical oxygen evolution reaction. The in-situ reconstructed Ga-O-Ir interface sustains high water oxidation rates at OER overpotentials. We found that OER at the Ga-O-Ir interface follows a bi-nuclear adsorbate evolution mechanism with unsaturated IrOx as the active sites, while GaOx atoms play an indirect role in promoting water dissociation to form OH* and transferring OH* to Ir sites. This breaks the scaling relationship of the adsorption energies between OH* and OOH*, significantly lowering the energy barrier of the rate-limiting step and greatly increasing reactivity. The Ir@Ga2O3 catalyst achieves lower overpotentials, a current density of 2 A cm-2 at 1.76 V, and stable operation up to 1 A cm-2 in scalable PEM electrolyzers at 1.63 V, maintaining stable operation at 1 A cm-2 over 1000 hours with a degradation rate of 11.5 μV h-1. This work prompted us to jointly address substrate-catalyst interactions and catalyst reconstruction, an underexplored path, to improve activity and stability in Ir PEMWE anodes.