P‐Orbital Bismuth Single‐Atom Catalyst for Highly Effective Oxygen Electroreduction in Quasi‐Solid Zinc‐Air Batteries

Abstract P‐block metals have gradually been utilized to synthesize non‐noble‐metal catalysts for oxygen reduction reaction (ORR) due to the easily tunable localizedp‐orbitals and resulted versatile electronic structures. The high‐density single‐atom bismuth sites (Bi−NC) anchored onto nitrogen‐doped three‐dimensional porous carbon are proved to possess significant electrocatalytic ORR performance. Theoretical calculations unveil positively charged bismuth centers prominently improved the adsorption capacity of N‐doped carbon to O2. Theporbitals of Bi sites within Bi−NC easily generate hybrid states withporbitals of O2, thus promoting charge transfer and ultimately reducing the energy barrier of ORR. Benefiting fromp‐orbital electrons regulation of bismuth atoms, Bi−NC exhibit ORR half‐wave potential of 0.86 V (vs RHE). Additionally, both liquid and quasi‐solid zinc‐air batteries with Bi−NC as air‐cathodes achieve higher power density and specific capacity than 20 wt% Pt/C, and comparable stability and round‐trip efficiency with 20 wt% Pt/C. The discovery sheds light on the theoretical and practical guidance forp‐block metallic single‐atom catalysts.