Recycling Synthesis of Single-Atom Zn-nitrogen-carbon Catalyst for Electrocatalytic Reduction of O2 to H2O2

Portable electrochemical synthesis of H2O2,which is widely used for disinfection,sterilization,and waste treatment,has attracted increasing attention.However,low atomic utilization efficiency and by-product disposal during the synthesis of electrocatalysts are inevitable.Based on the advantages of single-atom catalysts(SACs)towards H2O2 synthesis via a 2e transfer oxygen reduction reaction,this work presents the synthesis of ZnNC SACs as excellent oxygen reduction catalysts with high atomic use efficiency and almost no generated waste by using formamide and metal powder as precursors.The ZnNC SACs exhibit H2O2 selectivity exceeding 80％when working continuously for 10,000 s.The synthetic strategy described in this paper is intended to be used as a supplement to the synthesis of metal-nitrogen-carbon SACs with high atomic utilization efficiency and low waste genera-tion for environmental and chemical applications.