Support-tuned iridium reconstruction with crystalline phase dominating acidic oxygen evolution
Kexin Zhang, Xiao Liang, Yucheng Wang, Yongcun Zou, Xiao Zhao, Hui Chen, Xiaoxin Zou
Abstract
Abstract The dynamic reconstruction of oxygen evolution electrocatalysts dictates their performance, yet conventional Ir-based materials face an inherent activity-stability trade-off due to surface amorphization into hydrous IrO x phases accompanied by lattice oxygen mechanisms. Here, we uncover a distinct reconstruction pathway for supported Ir nanoparticles, where a TiO x @Ti substrate drives a bulk phase transition from metallic Ir to crystalline rutile IrO 2 during electrocatalysis. Unlike surface-limited amorphization, this support-guided crystallization shifts the reaction mechanism from involving lattice oxygen mechanism to the complete adsorbate evolution mechanism, as confirmed by mechanistic and structural analyses. Consequently, the Ir/TiO x @Ti catalyst achieves both high activity and durability in acidic media, demonstrated in three-electrode systems and proton exchange membrane water electrolyzers. This work redefines support roles in electrocatalyst reconstruction, demonstrating that bulk phase engineering—rather than surface modification—resolves the long-standing efficiency-durability conflict in acidic oxygen evolution.