Integrating Pd–CNO2 into covalent organic framework enables efficient H2O2 photosynthesis from neutral water

Hydrogen peroxide (H 2 O 2 ) photosynthesis from H 2 O and O 2 remains a significant challenge due to the sluggish hydrogen donation process, which stems from the high O–H bond dissociation energy of water. In this study, we propose an effective strategy to accelerate the water oxidation reaction (WOR) by anchoring single palladium atoms (Pd–CNO 2 ) onto a keto-anthraquinone covalent organic framework (KfAQ-Pd), achieving remarkable H 2 O 2 production rates of 3828 μmol h −1 g −1 under visible light irradiation ( λ > 420 nm) in neutral water. Both experimental observations and theoretical simulations reveal that the Pd–CNO 2 configuration induces an upward shift in the d-band center and enhances the hydrophilicity of KfAQ. This modification effectively disrupts the hydrogen-bond network within adsorbed water clusters, thereby promoting the cleavage of the dangling O–H bonds in H 2 O molecules and facilitating efficient hydrogen donation. The generated H 3 O + species are subsequently reduced in-situ by photogenerated electrons, leading to the hydrogenation of anthraquinone moieties and ultimately driving efficient H 2 O 2 photosynthesis. Overall, these findings highlight the pivotal role of single Pd atoms in enhancing water dissociation and hydrogen transfer, offering a promising new paradigm for solar-driven, environmentally friendly H 2 O 2 synthesis in neutral aqueous systems.