Suppressing iridium over-oxidation via catalyst–support interactions on tungsten oxide nanowires revealed by in-situ XPS for durable, low-loaded PEM water electrolysis, Applied Catalysis B: Environment and Energy, 382,125919(2026)
Lu-Yu Chueh, Yu-Chen Chien, Yu-Wei Hsu, Zun-Wei Wang, Ding-Huei Tsai, Chang-Ming Wu, Shao-Chu Huang, Hsiang-Jung Chen, Han-Yi Chen, Meng-Hsuan Tsai, Chia-Hsin Wang, Chueh-Cheng Yang*, Yung-Tin (Frank) Pan*
2026/05/07
The intrinsically high cost of iridium and the poor stability of iridium-based catalysts under low-loading conditions in proton exchange membrane water electrolysis (PEMWE) remain major obstacles to large-scale deployment. A solution-phase loading method is developed to enable uniform anchoring and activation of iridium oxide (IrOx) nanoparticles on tungsten oxide nanowire (WOxNW). The resulting IrOx/WOxNW heterostructure exhibits enhanced oxygen evolution reaction (OER) activity and stability under acidic conditions. In-situ near-ambient-pressure X-ray photoelectron spectroscopy reveals effective suppression of Ir over-oxidation to high-valent species (>4+), a degradation pathway evident in Ir Black. Non-destructive XPS depth profiling shows that WOx helps stabilize a core–shell structure composed of a metallic Ir0 core and an Ir4+ shell, whereas Ir Black becomes fully oxidized under similar conditions. Together with DFT calculations, this structural feature provides a theoretical basis for the improved OER kinetics. The catalyst achieves a low degradation rate of 15.7 µV h−1 over 100 h and minimal Ir leaching (0.003 ppm) during half-cell testing at 10 mA cm−2. In PEMWE operation, it delivers 1 A cm−2 at 1.61 V for over 200 h with an Ir loading of only 0.33 mgIr cm−2. This work represents one of the few in-situ studies linking catalyst–support interactions to degradation suppression, offering a promising solution toward durable, low-Ir electrolyzers for green hydrogen production.
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