Vacancy-Enhanced Sb–N<sub>4</sub> Sites for the Oxygen Reduction Reaction and Zn–Air Battery
Ying Zhang, Zhiwen Chen, Xu Liu, Zi Wen, Chandra Veer Singh, Chun Cheng Yang, Qing Jiang
Abstract
With the advantages of a Fenton-inactive characteristic and unique p electrons that can hybridize with O 2 molecules, p-block metal-based single-atom catalysts (SACs) for the oxygen reduction reaction (ORR) have tremendous potential. Nevertheless, their undesirable intrinsic activity caused by the closed d 10 electronic configuration remains a major challenge. Herein, an Sb-based SAC featuring carbon vacancy-enhanced Sb–N 4 active centers, corroborated by the results of high-angle annular dark-field scanning transmission electron microscopy and X-ray absorption fine structure, has been developed for an incredibly effective ORR. The obtained Sb SA –N–C demonstrates a positive half-wave potential of 0.905 V and excellent structural stability in alkaline environments. Density functional theory calculations reveal that the carbon vacancies weaken the adsorption between Sb atoms and the OH* intermediate, thus promoting the ORR performance. Practically, the Sb SA –N–C-based Zn–air batteries achieve impressive outcomes, such as a high power density of 181 mW cm –2, showing great potential in real-world applications.