Cobalt nanoparticles anchored on N-doped carbon nanosheets to facilitate the oxygen reduction kinetics in green sustainable Zn-air and Mg-air batteries

The developing of the advanced electrocatalysts with low-cost, highly active, and splendid stability towards oxygen reduction reaction (ORR) remains a vital and challenging bottleneck for commercialization of the metal-air batteries. Here, Co/NC electrocatalytic materials with abundant surface active sites and structural defects were obtained by anchoring metal cobalt nanoparticles onto N-doped carbon nanosheets through convenient solvothermal-pyrolysis strategy. The strategy could regulate the electronic structure and accelerate kinetics towards ORR, which showed excellent ORR catalytic activity and stability comparable to the commercial Pt/C. Meanwhile, the performance of Zn-air and Mg-air batteries assembled with Co/NC as the air-cathode were better than that of commercial Pt/C. This research provided a possibility for non-precious metal-based ORR electrocatalysts in green sustainable metal-air batteries. Ultrasmall cobalt nanoparticles were anchored on N-doped carbon nanosheets, which demonstrated excellent activity and stability in ORR comparable to commercial Pt/C, and the assembled Zn-air and Mg-air batteries has high specific capacity and stability. • Ultrasmall cobalt nanoparticles were anchored on N-doped carbon nanosheets by pyrolysis method. • Co/NC had abundant surface active sites, structural defects, and incomplete d-orbital electrons. • Co/NC demonstrated excellent activity and stability in ORR comparable to commercial Pt/C. • The assembled green sustainable Zn-air and Mg-air batteries had high specific capacity and stability.