Yang, Chenlu; Zhu, Yanping; Zhang, Fengru; Yao, Longping; Chen, Yihe; Lu, Tongchan; Li, Qixuan; Li, Jun; Wang, Guoliang; Cheng, Qingqing; Yang, Hui

ADVANCED MATERIALS

2025, 38,

Yang, Chenlu; Zhu, Yanping; Zhang, Fengru; Yao, Longping; Chen, Yihe; Lu, Tongchan; Li, Qixuan; Li, Jun; Wang, Guoliang; Cheng, Qingqing; Yang, Hui

Achieving high activity and stability while minimizing Ir usage poses a significant challenge in the industrialization of proton exchange membrane water electrolysis (PEMWE). Herein we report a sulfur-doping strategy that enables the OER pathway on IrO2 nanoparticles (IrO2/S) to switch from conventional adsorption evolution mechanism (AEM) to lattice oxygen mechanism (LOM) while maintaining Ir & horbar;O bond stability, thus achieving a significant enhancement in both intrinsic activity and durability. Advanced spectroscopies and theoretical calculations reveal that the Ir & horbar;S coordination motif within the lattice increases the electron density of the Ir center and enhances Ir & horbar;O covalency, thus triggering the LOM pathway. Importantly, the lattice distortion and unsaturated Ir & horbar;O coordination within the IrO2/S generate the oxygen nonbonding state that acts as an electron sacrificial agent to preserve Ir & horbar;O bonds upon the LOM-dominated OER process. As a result, PEMWE integrated with such IrO2/S electrocatalyst delivers a low cell voltage (1.769 V at 2.0 A cm-2) and long-term stability (16.6 mu V h(-)(1) over 1000 h@1.0 A cm(-)2) while dramatically reducing Ir usage from 1.0 to 0.3 mg cm-2. This work establishes S doping as a viable strategy to trigger LOM and stabilize lattice oxygen redox in Ir-based catalysts, opening a new avenue for low-Ir PEMWEs.