Boosting the Acidic Oxygen Reduction Activity of <i>p</i>‐Block Single‐Atomic Catalyst via <i>p</i>–<i>p</i> Orbital Coupling and Pore Engineering
Hu Wang, Yongjian Zhao, Jun Li, Xiaosha Wang, Murong Huang, Lei Zhang, Chenyang Zhao
Abstract
Atomically dispersed main group element single‐atom catalysts (SACs) have recently attracted increasing attention in electrocatalysis. However, their performances in acidic oxygen reduction reaction (ORR) remain unsatisfactory owing to the suboptimal coordination environment, limited mass transfer, and active site exposure. Herein, a series of p ‐block Sn SACs with hierarchical pore structures are prepared by a dual melting salt‐mediated soft template method. By deliberately regulating the pore structures, highly exposed Sn active sites with N/O coordination are obtained, which endow SnN 3 O‐50 with exceptional ORR performances, especially in acidic medium. The half‐wave potential of SnN 3 O‐50 is up to 0.816 V, with a loss of only 15 mV after 10 000 potential cycles. Furthermore, the peak power densities of the fuel cell and zinc–air battery assembled using SnN 3 O‐50 as cathodes reach 502 and 173.5 mW cm −2 , respectively, demonstrating great potential for practical applications. Density functional theory (DFT) calculations reveal that the N/O coordination of Sn induces localization of 5 p electrons, which leads to strong coupling with the p orbit of O 2 . Meanwhile, the presence of defects synergistically regulates the adsorption of reaction intermediates, thereby optimizing the free energy of the four successive ORR steps.