Manganese, nitrogen co-doped porous carbon with high-loading active sites as the oxygen reduction catalyst for Zn-air batteries

Manganese-nitrogen-carbon (Mn-N-C) materials have been considered ideal catalysts for the oxygen reduction reaction (ORR). However, avoiding metal agglomeration during pyrolysis while ensuring the construction of Mn-N_x active centers is still difficult. Furthermore, the influence of pyrolysis temperature on structures of Mn-N-C is controversial, and needs an in-depth understanding. Herein, we prepare single atom Mn-N-C via a spatial confinement method. This is achieved through the pyrolysis of the ZIF precursor, where single Mn(acac)₃ molecules are trapped within its cavities. Compared with 800 °C and 1000 °C, 900 °C is the optimal pyrolysis temperature for the synthesis of ZIF-derived Mn-N-C, which promotes the formation of the porous framework and dense Mn-N_x centers (27.47%). As a result, Mn-N-C-900 possesses an outstanding performance with a half-wave potential (E_1/2) of 0.882 V in alkaline media.