Thermal Migration Promotes the Formation of Manganese and Nitrogen Doped Polyhedral Surface for Boosted Oxygen Reduction Electrocatalysis.

Increasing the oxygen reduction reaction (ORR) catalytic activity of carbon-based electrocatalysts with robust stability is of great significance for their application. Herein, a feasible thermal migration strategy was proposed to construct manganese- and nitrogen-doped carbonaceous polyhedron frameworks coupled with manganese monoxide microrods (MnO-NC). Mn species were migrated to the surface of polyhedron frameworks, the shape of which was maintained at the high-temperature treatment. The Mn thermal migration not only created highly dispersed Mn-N x active sites but also promoted graphitization, which benefited ORR electrocatalysis. Moreover, the MnO microrod-supported polyhedron frameworks provide beneficial mass transfer channels for electrocatalysis. Therefore, MnO-NC exhibited impressive ORR catalytic activity and stability in both alkaline and neutral electrolytes compared to commercial Pt/C catalysts. A magnesium-air battery (MAB) driven by MnO-NC delivered a high open circuit voltage and peak power density comparable to that driven by Pt/C. Notably, MnO-NC-driven MAB possessed a longer discharge time than the Pt/C-driven one, indicative of the superior catalytic performance of Mn-NC. This work provides a simple but effective strategy to construct carbonaceous framework electrocatalysts for boosted ORR, promoting the widespread application of metal-air batteries and fuel cells.