The role of various components in Ru-NiCo alloys in boosting the performance of overall water splitting.

Understanding the synergistic mechanism of multi-component alloys is crucial and challenging for overall water splitting. Herein, Ru-NiCo-600 °C and Ru-NiCo with excellent electrocatalytic activity are designed and synthesized. The Ru-NiCo-600 °C alloy exhibits remarkable HER activity with an overpotential of 42, 77 and 93 mV at 10 mA cm in alkaline, acidic and neutral conditions, and the Ru-NiCo electrocatalyst presents outstanding OER activity with an overpotential of 176 mV at 10 mA cm in 1.0 M KOH. The Ru-NiCo-600 °C ||Ru-NiCo cell requires only 1.48 and 1.69 V to reach 10 and 100 mA cm towards overall water splitting. A series of experiments reveal that the strong electronic coupling among Ru, Ni and Co regulates the electronic structure and enhances the intrinsic catalytic activity and stability of the as-synthesized Ru-NiCo electrocatalysts. Systematic experimental and theoretical results prove that Ni atoms act as the active sites of dissociating water, while Ru and Co are respectively the active centers of proton and hydroxyl adsorption for HER and OER. Our work provides a new perspective for profoundly understanding the synergistic effect of multi-component alloys towards water splitting.