Mitigating Irreversible Ru Dissolution in Acidic OER via Controlled Co‐Induced Reconstruction of RuCo Alloy Electrocatalysts

Abstract A deep understanding of the surface reconstruction process is essential for developing efficient electrocatalysts for oxygen evolution reaction (OER). Herein, a comprehensive exploration is conducted by utilizing RuCo alloy nanoparticles as a model catalyst to investigate the surface process during acidic OER and the impact on performance, through the combination of electrochemical analysis and experimental characterization. Interestingly, it is observed that the RuCo alloy catalyst undergoes surface dynamic reconstruction during the OER reaction, forming a new ultrathin active phase CoRuO _x (Ru‐doped Co ₃ O ₄ ), which effectively prevents Ru overoxidation and dissolution, thereby enhancing stability. Moreover, it can also facilitate water adsorption and dissociation, accelerate the formation of the *OOH intermediate, promote the adsorbate evolution mechanism (AEM) mechanism, and significantly improve the catalytic activity. Consequently, the RuCo alloy catalyst exhibits appealing performance compared to pure Ru particles and commercial RuO ₂ , with an overpotential of 210 mV to reach 10 mA cm ⁻² , and an improved stability for over 120 h.