Hybrid shells of N-doped carbon encapsulated by MnO nanoparticles as oxygen reduction reaction electrocatalysts

Recently, the development of non-precious metal electrocatalysts for effective oxygen reduction reaction (ORR) has become a research hotspot. Herein, a facile and effective strategy is explored to develop non-precious electrocatalysts of hybrid shells of N-doped carbon (N-carbon) encapsulated by MnO (denoted as MnO/N-carbon/MnO), which can be recognized as efficient and durable electrocatalysts for ORR. The MnO2/N-carbon/MnO2 hybrid shells were synthesized via the redox reaction between poly(o-phenylenediamine) (PoPD) hollow microspheres and KMnO4, followed by a calcination process to form MnO/N-carbon/MnO hybrid shells. The cyclic voltammetry (CV) and linear scanning voltammetry (LSV) proved that MnO/N-carbon/MnO(800) hybrid shells showed the best electrocatalytic activity for ORR. The hybrid structure of the material and the synergy between MnO and N-carbon contribute to the improved electrocatalytic activity for ORR.