Support-tuned iridium reconstruction with crystalline phase dominating acidic oxygen evolution.
basic_science · Level V
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- Record sourced from PubMed, PMID 40890137.
- Also identified by DOI 10.1038/s41467-025-63541-9 and PMC identifier 12402471.
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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<sub>x</sub> phases accompanied by lattice oxygen mechanisms. Here, we uncover a distinct reconstruction pathway for supported Ir nanoparticles, where a TiO<sub>x</sub>@Ti substrate drives a bulk phase transition from metallic Ir to crystalline rutile IrO<sub>2</sub> 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<sub>x</sub>@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.