Stability of Multivalent Ruthenium on CoWO₄ Nanosheets for Improved Electrochemical Water Splitting with Alkaline Electrolyte

Abstract

Engineering low‐cost electrocatalysts with desired features is vital to decrease the energy consumption but challenging for superior water splitting. Herein, we development a facile strategy by the addition of multivalence ruthenium (Ru) into the CoWO4/CC system. During the synthesis process, the most of Ru3+ ions were insinuated into the lattice of CoWO4, while the residual Ru3+ ions were reduced to metallic Ru and further attached to the interface between carbon cloth and CoWO4 sheets. The optimal Ru2(M)‐CoWO4/CC exhibited superior performance for the HER with an overpotential of 85 mV@10 mA cm−2, which was much better than most of reported electrocatalysts, regarding OER, a low overpotential of 240 mV@10 mA cm‐2 was sufficient. In comparison to Ru2(0)‐CoWO4/CC with the same Ru mass loading, multivalence Ru2(M)‐CoWO4/CC required a lower overpotential for OER and HER, respectively. The Ru2(M)‐CoWO4/CC couple showed excellent overall water splitting performance at a cell voltage of 1.48 V@10 mA cm‐2 for used as both anodic and cathodic electrocatalysts. Results of the study showed that the electrocatalytic activity of Ru2(M)‐CoWO4/CC was attributed to the in‐situ transformation of Ru/Co sites, the multivalent Ru ions and the synergistic effect of different metal species stimulated the intrinsic activity of CoWO4/CC.