MnCo 2 O 4 Anchored on Nitrogen‐Doped Carbon Nanomaterials as an Efficient Electrocatalyst for Oxygen Reduction

The hybrids composed of N‐doped carbon (N−C) and transition‐metal‐based nanoparticles have attracted tremendous interest due to their outstanding catalytic performance for oxygen reduction reaction (ORR). Herein, we first synthesize a N−C nanomaterial by pyrolyzing the mesoporous‐silica‐protected zeolitic imidazolate framework‐8 (ZIF‐8). The synthesis involves formation of ZIF‐8@SiO 2 core‐shell structure, thermal annealing in Ar and acid etching. Then, the MnCo 2 O 4 nanoparticles are supported on the as‐synthesized N−C via a facile solvothermal method. The obtained hybrid of MnCo 2 O 4 and N−C (MnCo 2 O 4 /N−C) exhibits better ORR activity than other as‐prepared contrast materials in terms of more positive half‐wave potential and larger diffusion‐limiting current density, close to the commercial Pt/C. Moreover, the MnCo 2 O 4 /N−C catalyst also shows better methanol tolerance and better operational stability than the benchmark Pt/C catalyst. The superior performance of MnCo 2 O 4 /N−C is attributed to its porous structure and large BET surface area, N‐doping effect, small size MnCo 2 O 4 nanoparticles loaded on the porous N−C and synergistic effects between the doped active species. Therefore, it is expected to replace Pt/C as a promising fuel cell catalyst in alkaline direct methanol fuel cells.