Alginate derived Co/N doped hierarchical porous carbon microspheres for efficient oxygen reduction reaction

Exploring biomass-derived non-precious metal carbon-based electrocatalysts have attracted intensive interest in the field of energy conversion due to their low-cost, ecofriendly and sustainable. Herein, we report a novel strategy for preparation of Co/N doped hierarchical porous carbon microspheres (Co/NHPCMS), via pyrolysis ZIF-67@SA/NaHCO3 microspheres prepared by in-situ growth of ZIF-67 on electrospray Co-SA/NaHCO3 microspheres. ZIF-67 nanocrystals were well distributed on the ions cross-linked alginate/NaHCO3 microspheres. The pyrolysis of ZIF-67@SA/NaHCO3 microspheres could provide abundant active sites and rich porous structure. More importantly, NaHCO3 plays an essential role in obtaining large mesopores and high pore volume, which is benefit to facilitate the diffusion of reactants. With these merits, Co/NHPCMS-600 exhibits an outstanding ORR electrocatalytic performance with a half-wave potential of 0.827 V. Besides, Co/NHPCMS-600 catalyst exhibits superior catalytic stability and tolerance to methanol in the ORR. This work provides a promising route based on sustainable biomass toward high performance electrocatalyst in the field of energy conversion.