Fine Engineering of d-Orbital Vacancies of ZnN<sub>4</sub> via High-Shell Metal and Nonmetal Single-Atoms for Efficient and Poisoning-Resistant ORR
Xiaoyuan Sun, Xinyi Li, Hong Huang, Wenting Lu, Xiaochun Xu, Xiaoqiang Cui, Lu Li, Xiaoxin Zou, Weitao Zheng, Xiao Zhao
Abstract
Atomically dispersed metal–nitrogen–carbon (M–N–C) materials are active oxygen reduction reaction (ORR) catalysts. Among M–N–C catalysts, ZnN 4 single-atom catalysts (SACs) due to a nearly full 3d 10 electronic configuration insufficiently activate oxygen and display low ORR activity. To finely engineer d-orbital vacancies of ZnN 4, we combine high-shell metal and nonmetal SAs as electronic regulators that are ZnN 4 Cl and carbon vacancy-hosted −Cl motifs, which show complementary electron-withdrawing capacities versus the ZnN 4 . Under that, the ZnN 4 exhibits significantly enhanced ORR activity with a half-wave potential ( E 1/2 ) of 0.912 V RHE relative to the unmodified ZnN 4 ( E 1/2 = 0.822 V RHE ) and simultaneously robust durability (negligible activity loss after 10,000 potential cycles). Particularly, the engineered ZnN 4 possesses high resistance to SCN – poisoning, which is rarely achieved among M–N–C SACs. Our works show that combining high-shell metal and nonmetal SAs can finely engineer d-orbital vacancies of metal centers to an optimal state, thereby intrinsically enhancing their catalytic performance.