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Abstract Developing efficient and robust electrocatalysts toward the oxygen evolution reaction (OER) is critical for proton exchange membrane water electrolysis (PEMWE). RuO 2 possesses intrinsically high OER activity, but the concurrent electrochemical dissolution leads to rapid deactivation. Here a unique RuO 2 catalyst containing metallic Ru─Ru interactions (m‐RuO 2 ) is reported, which maintains stability in practical PEMWE for 100 h at 60 °C and 1 A cm −2 . Experimental and theoretical investigations suggest that the presence of Ru─Ru interactions significantly increases the energy barrier for the formation of RuO 2 (OH) 2 , which is a key intermediate for Ru dissolution, and hence substantially mitigates the electrochemical corrosion of m‐RuO 2 . Meanwhile, the Ru4d band center downshifts, accordingly, ensuring the high OER activity, and the participation of lattice oxygen in the OER is also suppressed at the Ru─Ru sites, further contributing to the enhanced durability. Interestingly, such enhanced stability is also dependent on the size of metallic Ru─Ru cluster, where the energy barrier is further increased for Ru 3 , but is decreased for Ru 5 . These results highlight the significance of local coordination structure modulation on the electrochemical stability of RuO 2 and open a feasible avenue toward the development of robust OER electrocatalysts for high‐performance PEMWE.
Zhao et al. (Thu,) studied this question.