Mn–N3–O-Loaded Graphitic Carbon Aerogel for an Efficient Oxygen Reduction Reaction

Deleterious reactive oxygen species are frequently produced by some single-atom electrocatalysts via the Fenton reaction when they catalyze the oxygen reduction reaction (ORR). The single-atom electrocatalysts based on Mn are generally considered to have low Fenton reactivity. Herein, an atomically dispersed Mn–N3–O-loaded graphitic carbon aerogel (Mn–N–C) is prepared simply by heating a carbon aerogel and molten MnCl2 under ammonia gas. Mn–N–C exhibits approximately 0.900 V vs the reversible hydrogen electrode half-wave potential, and only 8 mV is lost after 5000 cycles, accelerating the durability test for the ORR in 0.10 mol/L KOH. In a zinc–air battery, Mn–N–C exhibits cycling stability over 350 h without a significant drop and a peak power density of 210 mW/cm2. Based on density functional theory calculations, X-ray absorption spectroscopy, and high-resolution TEM, the formation mechanism and high performance of the Mn–N3–O sites in Mn–N–C are well demonstrated. The strategy of heating the carbon aerogel and molten salts under ammonia gas might offer a universal method for metal–N–C synthesis.