Triggering charge redistribution-induced oxygen spillover mechanism in VO_x-supported IrSn alloy toward industrial water electrolysis.

Authors

Zijie Lin, Jiashun Liang, Hao Shi, Yuhan Wang, Yunze Song, Jiarui Liu, Yunan Li, Xiaoke Xi, Tanyuan Wang, Zhao Cai, Ruiguo Cao, Dong Su, Yunhui Huang, Qing Li

Published in

Science advances. Volume 12. Issue 32. Pages eaef7481. Aug 07, 2026. Epub Aug 05, 2026.

Abstract

Developing advanced iridium (Ir)-based oxygen evolution reaction (OER) catalysts is critical for proton exchange membrane water electrolyzers (PEMWEs). Unfortunately, conventional adsorbate evolution mechanism (AEM) and lattice oxygen mechanism (LOM) pathways suffer from an activity-stability trade-off, posing substantial challenges for catalyst design. Here, we report a charge-redistribution-induced oxygen (O) spillover strategy by designing amorphous VO_x-supported iridium-tin (IrSn) alloy OER catalysts, which can effectively transfer the poisoning oxygenated intermediates and maintain Ir valence stability (+2.5) during the dynamic OER to enhance activity and stability. In particular, the IrSn-VO_x-based PEMWE anode can deliver a current density of 3.0 amperes per square centimeter @ 1.798 volts (0.4 milligrams of platinum and Ir per square centimeter), surpassing the US Department of Energy (DOE) 2026 targets. A 25-square centimeter PEMWE operates stably for 5000 hours at industrial currents (≥25 amperes) with an exceptionally low degradation rate of 5.6 microvolts per hour, representing one of the best OER catalysts reported for practical PEMWEs. Theoretical calculations predict that the charge redistribution within IrSn-VO_x could reduce the kinetic energy barrier for *O spillover (from Ir to VO_x) by 69% relative to O-O coupling, thus triggering the O spillover against the Ir overoxidation/dissolution. Consequently, IrSn-VO_x follows a support-involved LOM pathway with a reduced rate-determining-step barrier (0.37 electron volts) relative to IrSn following AEM (0.66 electron volts). In addition, Sn doping in IrSn-VO_x can further promote the regeneration of VO_x lattice O and improve stability.

PMID:
42555715
Bibliographic data and abstract were imported from PubMed on 06 Aug 2026.

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