High-efficiency electrosynthesis of hydrogen peroxide from oxygen reduction enabled by a tungsten single atom catalyst with unique terdentate N₁O₂ coordination

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 (W₁/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 W₁/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.