In situ construction of N-doped hollow carbon polyhedron embedded with MnO/CoMn2O4 heterojunction nanoparticles by the metal anchoring effect as a bifunctional oxygen electrocatalyst toward Zn-air batteries

N doped hollow carbon polyhedron with abundant meso- and macropores was in situ constructed. • The metal anchoring effect led to N doped hollow carbon supported MnO/CoMn 2 O 4 heterojunction nanoparticles. • MnO/CoMn 2 O 4 @HNC exhibits an excellent bifunctional activities with a Δ E  = 0.711 V. • The battery has a peak power density of 168.6 mW cm −2 and a capacity of 788 mAh g −1 . Because of the sluggish kinetics of oxygen reduction/evolution reaction (ORR/OER) occurring at the air cathode, it is critical to develop efficient and sustainable bifunctional oxygen electrocatalysts for enhancing the real performance of Zn-air batteries (ZABs). Herein, we report a facile strategy to prepare MnO/CoMn 2 O 4 heterojunction nanoparticles embedded in N-doped hollow carbon polyhedron (MnO/CoMn 2 O 4 @HNC) through the metal anchoring effect. On the one hand, abundant meso- and macropores of the obtained MnO/CoMn 2 O 4 @HNC provide transport channels for oxygen molecules and reaction intermediates in the electrocatalytic process. On the other hand, density functional theory (DFT) calculations disclose that the interface coupling between MnO and CoMn 2 O 4 can facilitate electron transfer, and efficaciously reduce the energy barriers of rate determining steps (RDS) for ORR and OER. Owing to the advantages of structure and composition, MnO/CoMn 2 O 4 @HNC displays excellent electrocatalytic activity with a half-wave potential ( E 1/2 ) of 0.85 V for ORR and a potential of 1.561 V at 10 mA cm −2 for OER. The homemade ZABs driven by MnO/CoMn 2 O 4 @HNC perform a high power density of 168.6 mW cm −2 and a superb cycling stability (600 cycles). This work affords a promising route for in situ construction of non-precious metal bifunctional electrocatalysts with a novel structure toward ZABs. Download: Download high-res image (186KB) Download: Download full-size image