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Abstract

Single-atom catalysts (SACs) have shown great potential in the electrochemical oxygen reduction reaction (ORR) toward hydrogen peroxide (H2O2) production. However, current studies are mainly focused on 3d transition-metal SACs, and very little attention has been paid to 5d SACs. Here, a new kind of W SAC anchored on a porous O, N-doped carbon nanosheet (W-1/NO-C) is designed and prepared via a simple coordination polymer-pyrolysis method. A unique local structure of W SAC, terdentate W1N1O2 with the coordination of two O atoms and one N atom, is identified by the combination of aberration-corrected scanning transmission electron microscopy, X-ray photoelectron spectroscopy and X-ray absorption fine structure spectroscopy. Remarkably, the as-prepared W-1/NO-C catalyzes the ORR via a 2e(-) pathway with high onset potential, high H2O2 selectivity in the wide potential range, and excellent operation durability in 0.1 m KOH solution, superior to most of state-of-the-art H2O2 electrocatalysts ever reported. Theoretical calculations reveal that the C atoms adjacent to O in the W1N1O2-C moiety are the most active sites for the 2e(-) ORR to H2O2 with the optimal binding energy of the HOO* intermediate. This work opens up a new opportunity for the development of high-performance W-based catalysts for electrochemical H2O2 production.