Long-Range Regulation of Se Doping for Oxygen Reduction of Atomically Dispersed Sb Catalysts for Ultralow-Temperature Solid-State Zn–Air Batteries
Ziqiang Niu, Z.W. Lu, Zelong Qiao, Minghui Xing, Linkai Han, Shitao Wang, Dapeng Cao
Abstract
Regulating the p-orbital valence electrons of atomically dispersed main-group metals to improve the inherent electrocatalytic activity has attracted extensive concerns. Herein, we designed and synthesized an atomically dispersed Sb–SeNC catalyst containing SbN 2 C 2 and SeC 2 structures, which have been identified by X-ray absorption spectroscopy and density functional theory (DFT) calculations. Sb–SeNC exhibits a high activity for the oxygen reduction reaction (ORR), and a Sb–SeNC-based flexible solid-state zinc–air battery (ZAB) can work efficiently at −40 °C, with a peak power density of 54.1 mW cm –2 and a rate discharge operation of about 44 h. DFT calculations further confirm the long-range regulation mechanism of the SeC 2 moiety for the ORR of SbN 2 C 2 and obtain the volcano relationship of U onset vs the Se–N distance. When the Se–N distance is 7.4 Å, the adsorption ability of active site Sb can be regulated to an optimal state related to the RDS: *O → *OH, while the smaller Se–N distance in short-range would lead to the excessive attenuation of adsorption ability of active site and decrease of ORR activity, which therefore yields the long-range regulation effect of Se doping on the ORR activity of SbN 2 C 2 . This long-range regulation strategy may provide a promising approach to boost the catalytic activity of main-group metal catalysts to achieve its application in ultralow-temperature solid-state ZABs.