▎ 摘　　要

It is of vital importance to search for a nonprecious metal based sustainable and efficient oxygen reduction reaction (ORR) electrocatalyst for the next generation of energy conversion and storage technology. We herein report a hybrid bimetal material composed of MnO/Co nanoparticles encapsulated in nitrogen-rich graphene nanosheets (MnO/Co-N-G) as a high performance ORR catalyst in alkaline electrolyte. The MnO/Co-N-G catalyst is derived from Mn2+, Co2+ incorporated polydopamine (PDA) coated graphene oxide (GO) sheets via a carbonization process. The morphology, structure, and composition properties of as-prepared MnO/Co-N-G catalyst are systematically investigated. Electrochemical measurements show that the MnO/Co-N-G catalyst exhibits excellent ORR. activity superior to commercial Pt/C, featuring higher limiting current density, better methanol resistance, and excellent long-term durability in alkaline solution. The bimetal nanoparticles are believed to be responsible for the impressive ORR activity of the catalyst.