LAUSR

The sluggish nature of oxygen reduction reaction (ORR), oxygen evolution reaction (OER) coupled with the high cost of related noble metals catalysts stimulate the research of active non-noble metal or metal-free oxygen catalysts. Though metal-free catalysts have been reported a lot, less catalysts showing highly activity towards ORR&OER, especially for biomass waste materials. This paper introduces a top-down strategy to fabricate a series of a bifunctional metal-free catalyst derived from plant residue. Among them, the catalyst BRCAC8502 shows an excellent electrocatalytic performance towards both ORR and OER (E1/2 = 0.85 V, Ei=10 = 1.68 V vs RHE). A zinc-air battery equipped by catalyst BRCAC8502 even displays a superior performance to that of Pt/C-RuO2. The excellent ORR&OER performances are mainly attributed to 3D hierarchical structures and rich active sites of the catalyst, including N functional groups, oxygen vacancies and carbon defects. The strategy of preparing plant residues into the outstandi...