Chinese Journal of Catalysis ›› 2026, Vol. 85: 237-246.DOI: 10.1016/S1872-2067(26)64993-5

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Surface anions-mediated dynamic interfacial free water enriched microenvironment on RuO2 for efficient acidic oxygen evolution

Liqing Wua,b,1, Wenxia Huanga,1, Bingbing Zhaoa, Ping Caia(), Wei Luoa()   

  1. a College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, Hubei, China
    b School of Physics and Optoelectronic Engineering, Hainan University, Haikou 570228, Hainan, China
  • Received:2025-09-28 Accepted:2025-11-08 Online:2026-06-18 Published:2026-05-18
  • Contact: *E-mail: applecaiping@163.com (P. Cai),
    wluo@whu.edu.cn (W. Luo).
  • About author:

    1Contributed equally to this work.

  • Supported by:
    National Natural Science Foundation of China(22579132)

Abstract:

Recent studies have revealed that the slow kinetics of active free water molecule replenishment on the surface of catalyst can be the potential cause responsible for the sluggish reaction kinetics of oxygen evolution reaction (OER) under acidic electrolyte. However, engineering the dynamic interfacial water structure to form the free water enriched microenvironment has rarely been implemented due to the relatively inherent inert catalyst surface. Herein, we demonstrate that surface modification of ruthenium dioxide (RuO2) with PO43- anions (RuP0.4Ox) can effectively regulate the free water enriched microenvironment and significantly enhance the acidic OER performance. Experimental results including operando attenuated total reflectance surface-enhanced infrared absorption spectroscopy reveal that the introduction of PO43- species can manipulate the interfacial water structure, resulting in a free-H2O-enriched interfacial environment, which is conducive to the continuous supply of reactants. Moreover, theoretical studies indicate that the surface modified PO43- could facilitate proton transfer to the oxygen sites of the PO43- group, enabling a PO43--assisted adsorption evolution mechanism with enhanced reaction kinetics. Consequently, the obtained RuP0.4Ox catalyst, featuring a Ru-O-P local environment and modified by surface PO43- anions, displays a low overpotential of 200 mV at 10 mA cm-2 and operates stably for 500 h during the acidic OER process.

Key words: Ruthenium dioxide, Acidic oxygen evolution reaction, Interfacial water structure, Surface anion modification