Manganese decoration tailored nitrogen doping for boosted oxygen reduction electrocatalysis of Co-NC

Increasing the oxygen reduction reaction (ORR) electrocatalytic performance of cobalt-nitrogen carbon (Co-NC) materials is highly desired for promoting their widespread application. Yet, it remains challenging due to the existence of activity gap between Co-NC and commercial Pt/C catalyst. Herein, an in-situ decoration strategy was proposed to construct a series of manganese tailored Co-NC (CoxMn-NC, where x represents the molar ratio of Co/Mn) electrocatalysts, which not only increased the content of active metal-Nx sites but also enhanced the graphitized degree of carbon skeleton. The optimal Co0.2Mn-NC exhibited higher half-wave potentials (0.868 V; 0.594 V) than Pt/C (0.838 V; 0.580 V) and robust catalytic stability in alkaline and neutral electrolytes, which was attributed to the tailored nitrogen doping and enhanced graphitized degree. Impressively, a magnesium-air battery driven by Co0.2Mn-NC exhibited better discharging performance than one driven by Pt/C, with a high open circuit voltage (1.61 V), a large peak power density of 83.17 mW cm−2, and a long discharge time of> 87 h at 20 mA cm−2. This work highlighted the promising potential of Mn decorated Co-NC for ORR related energy conversion. •We adopted a in-situ Mn decoration strategy to tailor the N-doping features of Co-NC.•Mn decoration promoted the formation of metal-Nx moieties and improved the graphitization of carbon skeleton.•The Co0.2Mn-NC exhibited impressive ORR catalytic activities in alkaline and neutral electrolytes.