Carbon nanotubes intercalated Co/N-doped porous carbon nanosheets as efficient electrocatalyst for oxygen reduction reaction and zinc–air batteries

Earth abundant transition-metals and nitrogen co-doped carbon (M-N/C) materials are particularly attractive as the most viable alternative to precious metal catalysts. Herein, a high-performance catalyst is prepared by building a carbon nanotubes (CNTs) intercalated Co/N-doped few layered carbon nanosheet (CNTs-Co/NC) hybrid with a unique open-ended porous structure. To prepare the catalyst, polyaniline molecules are first polymerized on carbon nanotubes and subsequent thermal annealing, resulting in formation of CNTs-Co/NC. For the CNTs-Co/NC catalyst, its surface area and pore volume are as high as 1072 m²/g and 0.63 cm³/g, respectively. As expected, it displays high ORR performance with an onset and a half wave potential of 0.96 V and 0.84 V (vs. RHE), respectively, in alkaline media. Impressively, when used as a cathode catalyst for zinc-air batteries, CNTs-Co/NC also exhibits a peak power density up to 83 mWcm⁻² with long-term durability and high rate capacity. Such enhanced performance can be attributed to the synergistic effect of the abundant Co/N coupling centers, the high surface area with more exposed active sites, and the high porosity accessible to ion transport.