Bias‐Induced Ga−O‐Ir Interface Breaks the Limits of Adsorption‐Energy Scaling Relationships for High‐Performing Proton Exchange Membrane Electrolyzers
Yinnan Qian, Yirun Guo, Zijie Yang, Zhaoyan Luo, Lei Zhang, Qianling Zhang, Chuanxin He, Hao Zhang, Xueliang Sun, Xiangzhong Ren
Abstract
Abstract 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@Ga 2 O 3 for the electrochemical oxygen evolution reaction. The in situ reconstructed Ga−O−Ir interface sustains high water oxidation rates at oxygen evolution reaction (OER) overpotentials. We found that OER at the Ga−O−Ir interface follows a bi‐nuclear adsorbate evolution mechanism with unsaturated IrO x as the active sites, while GaO x 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@Ga 2 O 3 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 proton exchange membrane water electrolyzer (PEMWE) 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.