Interfacial engineering-induced Janus heterostructures with enhanced electronic regulation for efficient oxygen electrocatalysis in rechargeable Zn-air batteries

Construction of efficient non-noble metal electrocatalysts for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are extremely important for zinc-air batteries (ZABs). Herein, a novel Janus heterostructure, coupling CeO2 with bimetallic metal sulfides (ZnCoS) with precise heterointerfaces, was designed through an interfacial engineering-induced strategy. Benefiting from the interfacial synergistic effect, the asymmetric Janus heterostructure of CeO2/ZnCoS (J−CeO2/ZCS) exhibits satisfactory ORR and OER activity, in terms of E1/2 of 0.87 V for ORR and overpotential of 290 mV for OER. Theoretical calculation further demonstrates that the heterointerface effectively modulates the electronic structure and charge redistribution, thus improving redox reactivity of active sites and the absorption/desorption of reaction intermediates. When the J-CeO2/ZCS applied in liquid and flexible ZABs as air cathodes, the devices deliver excellent power density and cycling stability. This Janus structure of composite catalysts affords a new opportunity for designing efficient oxygen electrocatalysts with heterostructures.