Active-N-Dominated Carbon Frameworks Supported CoNC Integrated with Co Nanoparticles as an Enhanced Bifunctional Oxygen Catalyst

[Formula: see text]–N x –C ([Formula: see text]=Fe, Co, etc.) substances received tremendous attention due to its outstanding performance for oxygen reduction reaction and oxygen evolution reaction. Usually, metal nanoparticles could form simultaneously during synthesis process, whereas these nanoparticles received very little attention since they were often removed by acid etching. Here, we designed and synthesized an active-N-dominated Co, N co-doped carbon layers supported Co nanoparticles material (denoted as CoNPs@CoNC) by annealing the composites of Co-Phen confined in porous carbon supports together with urea at 900 ∘ C. Compared with the acid etching CoNC catalyst without the surface Co nanoparticles, CoNPs@CoNC catalyst exhibited a higher Co content and slightly positive shifting of the main peak of Co 2p3/2 that is closely associated with the tuned electronic structure. Additionally, the as-prepared CoNPs@CoNC catalyst provided a superior performance ([Formula: see text][Formula: see text]V versus RHE, [Formula: see text][Formula: see text]V) than that of CoNC catalyst ([Formula: see text][Formula: see text]V, [Formula: see text][Formula: see text]V), which led to a lower reversible overvoltage of 0.73[Formula: see text]V for CoNPs@CoNC. Furthermore, the superior performance enabled the CoNPs@CoNC-based Zn–air battery catalyst with a more admirable charge-discharge performance in terms of open-circuit voltage, energy density and power density, unveiling its immense potential in realistic utilization.