Rational Design of Core@shell Structured CoS_x@Cu₂MoS₄ Hybridized MoS₂/N,S-Codoped Graphene as Advanced Electrocatalyst for Water Splitting and Zn-Air Battery

A novel hybrid of small core@shell structured CoS_x@Cu₂MoS₄ uniformly hybridizing with a molybdenum dichalcogenide/N,S-codoped graphene hetero-network (CoS_x@Cu₂MoS₄-MoS₂/NSG) is prepared by a facile route. It shows excellent performance toward the oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER) in alkaline medium. The hybrid exhibits rapid kinetics for ORR with high electron transfer number of ≈3.97 and exciting durability superior to commercial Pt/C. It also demonstrates great potential with remarkable stability for HER and OER, requiring low overpotential of 118.1 and 351.4 mV, respectively, to reach a current density of 10 mA cm⁻². An electrolyzer based on CoS_x@Cu₂MoS₄-MoS₂/NSG produces low cell voltage of 1.60 V and long-term stability, surpassing a device of Pt/C + RuO₂/C. In addition, a Zn-air battery using cathodic CoS_x@Cu₂MoS₄-MoS₂/NSG catalyst delivers a high cell voltage of ≈1.44 V and a power density of 40 mW cm⁻² at 58 mA cm⁻², better than the state-of-the-art Pt/C catalyst. These achievements are due to the rational combination of highly active core@shell CoS_x@Cu₂MoS₄ with large-area and high-porosity MoS₂/NSG to produce unique physicochemical properties with multi-integrated active centers and synergistic effects. The outperformances of such catalyst suggest an advanced candidate for multielectrocatalysis applications in metal-air batteries and hydrogen production.