Oxygen spillover engineering design in atomically dispersed sites for high-efficiency photoproduction of hydrogen peroxide from water

Abstract

The photocatalytic non-sacrificial hydrogen peroxide (H₂O₂) production is a sustainable and cost-effective approach to solar-driven chemical synthesis, yet its efficiency is fundamentally restricted by the competitive 4e⁻ water oxidation reaction with inefficient kinetics and insufficient atom utilization. Herein, we propose an oxygen spillover strategy to suppress the 4e⁻ water oxidation reaction, in which the O* on a metal atom spontaneously migrates and couples with OH* on a carbon atom, leading to the formation of OOH* in peroxy–ether intermediates for selective H₂O₂ synthesis. This new strategy is successfully implemented with nickel atom anchored carbon dots/covalent organic frameworks (Ni-CDs/COFs), achieving a record H₂O₂ evolution rate, an apparent quantum yield and a solar-to-chemical conversion efficiency of 11 603 µmol h⁻¹ g⁻¹, 20.4% at 420 nm and 1.56% under simulated sunlight, all outperforming those of most photocatalytic systems in pure water. The oxygen spillover enabled favorable formation of OOH* is further realized on diverse M-CDs with different types of metal atoms, demonstrating the feasibility and universality of the proposed strategy. This research opens a window for scalable solar-driven H₂O₂ production and pioneers an atomic-level design of the reaction pathway for efficient photosynthesis systems.