Pyridinic N[sbnd]B pair-doped carbon microspheres with refined hierarchical architectures for rechargeable zinc-air batteries

Refined architectures are of vital importance in determining the electrocatalytic activity of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Herein, pyridinic N[sbnd]B pair doped carbon microspheres (NB-CMS) with hierarchical micropore-mesopore structure are prepared via a SiO₂ hard template assisted CO₂ activation strategy. The pyridinic N[sbnd]B pair accounts for ≈ 59.9 % of all N species in NB-CMS, accelerating the ORR process with onset potential (0.996 V) and half-wave potential (0.889 V). Meanwhile, the NB-CMS also exhibits high OER performance with overpotential of 384 mV at 10 mA cm⁻². The assembled Zinc-air battery exhibits maximum power density of 134 mW cm⁻² and long-term charging and discharging stability over 358 h. Density functional theory (DFT) simulations reveal that the pyridinic N[sbnd]B pair exhibits the highest electrocatalytic performance in dual-functional catalysis, owing to the highest charge density and readily accepts electrons from *OOH adsorbate of N active site neighboring B.