Rational Construction of Atomically Dispersed Mn-N-x Embedded in Mesoporous N-Doped Amorphous Carbon for Efficient Oxygen Reduction Reaction in Zn-Air Batteries

Efficient single-atom transition metal-nitrogen-carbon (M-N-C) electrocatalysts are one of the most prospective alternatives to platinum-group metal (PGM)-based catalysts for oxygen reduction reaction (ORR) in the renewable energy area. However, their large scale application is quite challenging due to the lack of facile and cost-efficient synthetic strategies. Here, an atomically dispersed Mn-N-x on mesoporous N-doped amorphous carbon (MnNC) was engineered through pyrolyzing the Mn-N-x-containing complex generated by the reaction between Mn ions and phenanthroline. Owing to the atomically dispersed Mn-N-x moieties on the large mesoprous amorphous carbon, the resulting MnNC presents superb ORR performance evidenced by the half-wave potential of 0.86 V and the slight decay after long-time chronoamperometry tests, which surpasses commercial Pt/C and most reported Mn-based catalysts. Furthermore, the MnNC-based Zn-air battery delivers excellent performance, including a peak power density of 130.0 mW cm(-2) and a specific capacity of 819.0 mAh gZn(-1) as well as prominent durability that could continuously discharge for 60 h. This facile and scalable preparation approach provides a novel single-atom design direction for the architecture of high-performance ORR catalysts.