Tunnel-structured IrOx unlocks catalytic efficiency in proton exchange membrane water electrolyzers
Abstract
Abstract Proton exchange membrane water electrolyzers face challenges due to high iridium loading and sluggish oxygen evolution reaction kinetics when using conventional rutile-structured iridium oxide nanocatalysts. Here we find that iridium oxide catalysts with a specific tunnel-type crystal structure exhibit highly localized reactivity, where regions at tunnel mouths drive oxygen evolution far more efficiently than tunnel-wall regions. The intrinsic activity of tunnel mouths is 25-fold higher than that of tunnel walls, with shorter nanorods achieving a better balance between active site exposure and electron/mass transport efficiency. When implemented in proton exchange membrane water electrolyzers, this engineered catalyst achieves notable performance at low iridium loading (0.28 mgIr cm−2), delivering over 2.0 A cm−2 at 1.8 V (80 °C) and operating stably for 1800 h—notably outperforming conventional catalysts. Our work identifies catalytic hotspots in tunnel-structured oxides and demonstrates their rational integration into high-performance, durable electrolyzer systems.
Article Details
Authors (9)
Mingcheng Zhang
State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry
Wei An
Qianqian Liu
Key Laboratory of Polyoxometalate and Reticular Material Chemistry of Ministry of Education at Universities of Jilin Province Faculty of Chemistry
Yuzhu Jiang
Xiao Zhao
Hui Chen
Yongcun Zou
State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, 2699 Qianjin Street, Changchun 130012, P. R. China
Xiao Liang
Department of Chemistry
Xiaoxin Zou
State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry