Porous carbon nanosheets loaded Co4N as ORR/OER bifunctional catalysts for zinc-air battery

Efficient and durable oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) bifunctional electrocatalysts are critical for the development of zinc-air battery (ZAB). Unfortunately, conventional commercial catalysts usually display selective activity in only one reaction and cannot efficiently catalyze the two reactions at the same time. In this paper, porous carbon nanosheets loaded Co4N (Co4N/PNC) were prepared by pyrolysis of SiO2@ZnCo-ZIF. Due to the hierarchical pore structure, large specific surface area, abundant active sites, excellent electron transfer and mass transmission, the Co4N/PNC obtained at 920 degrees C (Co4N/PNC-920) exhibited outstanding ORR and OER catalytic activities. Furthermore, the assembled Co4N/PNC-920-based rechargeable ZAB displayed a discharge power density of 170.7 mW<middle dot>cm(-2), a specific capacity of 801.1 mA<middle dot>hg(-1) and an excellent durability, implying that Co4N/PNC-920 could be utilized as a bifunctional and highly active catalyst in ZABs.