Tri-functional Ru-RuO2/Mn-MoO2 composite: A high efficient electrocatalyst for overall water splitting and rechargeable Zn–air batteries

Preparation of highly efficient multi-functional electrocatalyst is extremely useful for application but quite challengeable. Herein, a new tri-functional Ru-RuO2/Mn-doped MoO2 (RRMM) electrocatalyst was successfully prepared through a facile solid phase reaction strategy. RRMM catalyst exhibits the small overpotential of 15 and 260 mV for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) at a current density of 10 mA cm−2, respectively. A low cell voltage of 1.53 V is required to achieve a current density of 10 mA cm−2 for overall water splitting. Meanwhile, a half-wave potential of 0.83 V was needed for oxygen reduction reaction (ORR) and assembled Zn–air battery exhibits an excellent stability. Density functional theoretical calculations also revealed that Ru-RuO2 active units facilitated reaction kinetics of HER and OER, while the synergistic effect of Ru and Mn-doped MoO2 endowed RRMM catalyst with excellent ORR activity.