Single‐Atom Zinc Sites with Synergetic Multiple Coordination Shells for Electrochemical H2O2 Production

Abstract

AbstractPrecise manipulation of the coordination environment of single‐atom catalysts (SACs), particularly the simultaneous engineering of multiple coordination shells, is crucial to maximize their catalytic performance but remains challenging. Herein, we present a general two‐step strategy to fabricate a series of hollow carbon‐based SACs featuring asymmetric Zn−N2O2 moieties simultaneously modulated with S atoms in higher coordination shells of Zn centers (n≥2; designated as Zn−N2O2−S). Systematic analyses demonstrate that the synergetic effects between the N2O2 species in the first coordination shell and the S atoms in higher coordination shells lead to robust discrete Zn sites with the optimal electronic structure for selective O2 reduction to H2O2. Remarkably, the Zn−N2O2 moiety with S atoms in the second coordination shell possesses a nearly ideal Gibbs free energy for the key OOH* intermediate, which favors the formation and desorption of OOH* on Zn sites for H2O2 generation. Consequently, the Zn−N2O2−S SAC exhibits impressive electrochemical H2O2 production performance with high selectivity of 96 %. Even at a high current density of 80 mA cm−2 in the flow cell, it shows a high H2O2 production rate of 6.924 mol gcat−1 h−1 with an average Faradaic efficiency of 93.1 %, and excellent durability over 65 h.