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

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 CoWO/CC system. During the synthesis process, the most of Ru ions were insinuated into the lattice of CoWO, while the residual Ru ions were reduced to metallic Ru and further attached to the interface between carbon cloth and CoWO sheets. The optimal Ru(M)-CoWO/CC exhibited superior performance for the HER with an overpotential of 85 mV@10 mA cm, which was much better than most of reported electrocatalysts, regarding OER, a low overpotential of 240 mV@10 mA cm was sufficient. In comparison to Ru(0)-CoWO/CC with the same Ru mass loading, multivalence Ru(M)-CoWO/CC required a lower overpotential for OER and HER, respectively. The Ru(M)-CoWO/CC couple showed excellent overall water splitting performance at a cell voltage of 1.48 V@10 mA cm for used as both anodic and cathodic electrocatalysts. Results of the study showed that the electrocatalytic activity of Ru(M)-CoWO/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 CoWO/CC.