Petal-Like N, O-codoped Carbon Nanosheets as Mott–Schottky nanoreactors in electrodes of Zn-Air Batteries and Supercapacitors

Abstract Heteroatoms-doped carbon nanosheets showed excellent electrocatalytic activity in oxygen reduction reaction (ORR). Herein, monoatomic Fe-N-C sites anchored on petal-like N, O-codoped carbon nanosheets surface were prepared using hemin chloride and were selected as Mott-Schottky nanoreactors in electrodes of Zn-air batteries and supercapacitors. Electron transport and mass transfer at the heterojunction interface between the nanosheets and Fe-N-C active sites were investigated thoroughly. Results indicated that not only petal-like nanosheets with abundant mesopores and high specific surface area could provide fast electrolytes diffusion path, but also the monoatomic Fe-N-C as Mott–Schottky nanoreactors was conducive to the electron transfer. The NGA-900@HC towards ORR under alkaline conditions showed a half-wave (E1/2) and onset potential (Eonset) of 0.85 and 1.16 V, respectively, which were better than those of Pt/C catalyst (vs. RHE) under a kinetic current density (JK) of 58.7 mA cm-2 at 0.55 V with the rotation rate of 1600 rpm and a limiting current density (JL) of 5.5 mA cm-2. This work provided an in-depth understanding of the correlation between ORR activity and work functions of doped mesoporous carbon materials.