Nitrogen-doped microporous carbon: An efficient oxygen reduction catalyst for Zn-air batteries

N-doped microporous carbon as an exceptional metal-free catalyst from waste biomass ( banana peel as representative) was obtained via fast catalysis carbonization, followed by N-doping modification. The method achieves a relatively high C conversion efficiency of similar to 41.9%. The final carbon materials are doped by N (similar to 3 at.%) and possess high surface area (similar to 1097 m(2) g (-1)) and abundant micropores. Compared to commercial Pt/C materials, the as-prepared carbon catalyst exhibits a comparable electrocatalytic activity and much better stability. Furthermore, the metal-free catalyst loaded Zn-air battery possesses higher discharge voltage and power density as compared with that of commercial Pt/C. This novel technique can also be readily applied to produce metal-free carbon catalysts from other typical waste biomass (e. g., orange peel, leaves) as the carbon sources. The method can be developed as a potentially general and effective industrial route to transform waste biomass into high value-added microporous carbon with superior functionalities. (C) 2017 Elsevier B. V. All rights reserved.