Rationally developing efficient and durable bifunctional catalysts toward oxygen reduction reaction(ORR)and oxygen evolution re-action(OER)is critical for rechargeable zinc-air batteries(ZABs).Herein,a bead-like CoSe2@NC@NCNFs bifunctional catalyst was de-signed and fabricated by confining cubic CoSe2 nanoparticles to three-dimensional(3D)porous MOFs-derived nitrogen-doped car-bon(NC)and one-dimensional(1D)N-doped carbon nanofibers(NCNFs)through a facile encapsulate strategy.The 1D/3D continu-ous network structure contributes to the improvement of specific surface area and electronic conductivity,while the strong synergis-tic effect between CoSe2 sites and Co-Nx-C sites can effectively enhance electron/mass transfer and reduce the diffusion resistance.The as-constructed CoSe2@NC@NCNFs catalyst exhibits high catalytic activity and stability toward ORR/OER with a high half-wave potential of 0.80 V(vs.RHE)in ORR and a low overpotential of 280 mV at 10 mA·cm-2 in OER.More encouragingly,the rechargeable ZABs with CoSe2@NC@NCNFs cathode deliver high peak power densities(126.8 mW·cm-2),large specific capacities(763.1 mA·h·g-1),and robust charge-discharge cycling stability over 240 cycles.This study provides a facile strategy for designing efficient bifunctional catalysts for rechargeable energy conversion applications.
万方数据
