Abstract
Metal/nitrogen-doped carbon single-atom catalysts (M-N-C SACs) show excellent catalytic performance with a maximum atom utilization and customizable tunable electronic structure. However, precisely modulating the M-N(x) coordination in M-N-C SACs remains a grand challenge. Here, we used a N-rich nucleobase coordination self-assembly strategy to precisely regulate the dispersion of metal atoms by controlling the metal ratio. Meanwhile, the elimination of Zn during pyrolysis produced porous carbon microspheres with a specific surface area of up to 1151 m(2) g(-1), allowing maximum exposure of Co-N(4) sites and facilitating charge transport in the oxygen reduction reaction (ORR) process. Thereby, the monodispersed cobalt sites (Co-N(4)) in N-rich (18.49 at%) porous carbon microspheres (CoSA/N-PCMS) displayed excellent ORR activity under alkaline conditions. Simultaneously, the Zn-air battery (ZAB) assembled with CoSA/N-PCMS outperformed Pt/C+RuO(2)-based ZABs in terms of power density and capacity, proving that they have good prospects for practical application.