Mn-N-C catalysts derived from metal triazole framework with hierarchical porosity for efficient oxygen reduction.

ABSTRACT

Manganese and nitrogen co-doped porous carbon (Mn-N-C) are proposed as one of the most up-and-coming non-precious metal electrocatalysts to substitute Pt-based in the oxygen reduction reaction (ORR). Herein, we chose metal triazole frameworks as carbon substrate with hierarchical porosity for trapping and anchoring Mn-containing gaseous species by a mild one-step pyrolysis method. The optimized Mn-N-C electrocatalyst with a large metal content of 1.71 wt% and a volume ratio of 0.86 mesopores pore delivers a superior ORR activity with a half-wave potential (E1/2) of 0.92 V in 0.1 M KOH and 0.78 V in 0.1 M HClO4. Moreover, the modified Mn-N-C catalyst showed superior potential cyclic stability. TheE1/2remained unchanged in 0.1 M KOH and only lost 6 mV in 0.1 M HClO4after 5000 cycles. When applied as the cathode catalyst in Zn-air battery, it exhibited a maximum peak power density of 176 mW cm-2, demonstrating great potential as a usable ORR catalyst in practical devices.