Epoxy Group Modified\nAtomic Zn–N<sub>2</sub>O<sub>2</sub> for H<sub>2</sub>O<sub>2</sub> Electrosynthesis and\nSulfide Oxidation

In this study, zinc single-atom catalysts (SACs) (Zn\nSACs) with\nZn–N<sub>2</sub>O<sub>2</sub> as the coordination shell and\nthe epoxy group (C–O–C) as the second coordination structure\nare synthesized. The obtained Zn SACs exhibit a high 2e<sup>–</sup> ORR selectivity of >85% in a wide potential window of 0–0.65\nV vs RHE and achieve a high generation rate of 828.9 mmol g<sub>cat</sub><sup>–1</sup> h<sup>–1</sup> for H<sub>2</sub>O<sub>2</sub>. Experimental and theoretical calculations have confirmed\nthat the second coordination structure of adjacent C–O–C\ncan effectively optimize the adsorption energy of Zn–N<sub>2</sub>O<sub>2</sub> for *OOH and tune the 2e<sup>–</sup> ORR\nselectivity. In addition, a small onset potential of 0.38 V vs RHE\nis achieved for sulfides oxidation reaction (SOR) by the obtained\nZn SACs. Moreover, a coupled system of anodic SOR and cathodic 2e<sup>–</sup> ORR is fabricated, which can save 45% energy consumption\ncompared to the OER-2e<sup>–</sup> ORR system due to a decreased\ncell voltage of 2.03 V at 20 mA cm<sup>–2</sup>. This study\nprovides new bifunctional Zn SACs modified by adjacent C–O–C,\nwhich are effective as bifunctional catalysts for electrosynthesis\nof H<sub>2</sub>O<sub>2</sub> and electro-oxidation of sulfides. These\ntwo reactions can be performed together in a coupled system with decreased\nenergy cost and thus should have better application potential.