High-entropy RuO<sub>2</sub> catalyst with dual-site oxide path for durable acidic oxygen evolution reaction.

Qian, Fangren; Cao, Dengfeng; Chen, Shuangming; Yuan, Yalong; Chen, Kai; Chimtali, Peter Joseph; Liu, Hengjie; Jiang, Wei et al. · Nat Commun · 2025

basic_science · Level V

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Abstract

Developing durable acidic oxygen evolution reaction catalysts is critical for industrial proton exchange membrane water electrolyzers. We incorporate high-entropy atoms (Co, Ni, Cu, Mn, Sm) into RuO<sub>2</sub> (RuO<sub>2</sub>-HEAE) via annealing, achieving remarkably high stability (>1500 h at 100 mA cm<sup>-</sup><sup>2</sup>). In situ differential electrochemical mass spectrometry and operando Attenuated Total Reflection Surface-Enhanced Infrared Absorption Spectroscopy reveal RuO<sub>2</sub>-HEAE follows a dual-site oxide path mechanism instead of the conventional adsorbate evolution mechanism. Quantitative Fourier-transformed extended X-ray absorption fine structure fitting and density functional theory calculations show this mechanistic shift stems from an elongated Ru-M distance in second coordination shell of RuO<sub>2</sub>-HEAE, enabling direct O-O coupling. This OPM-type catalyst delivers ~1500 h of stable operation at 1 A cm<sup>-</sup><sup>2</sup> and 50 °C, demonstrating superior durability versus most reported RuO<sub>2</sub>-based catalysts. This work provides fundamental insights for designing highly stable proton exchange membrane water electrolysis.