image: Fig. 1. Synthesis and characterization of KfAQ and KfAQ-Pd.
Credit: ©Science China Press
In a recent breakthrough published in Science Bulletin, Prof. Mingce Long’s team from the School of Environmental Science and Engineering at Shanghai Jiao Tong University reported a novel strategy for highly efficient photocatalytic synthesis of hydrogen peroxide (H2O2) from neutral water.
The study, titled “Integrating Pd–CNO2 into a covalent organic framework enables efficient H2O2 photosynthesis from neutral water” details how the group utilized a mechanochemical method to successfully incorporate a Pd–CNO2 coordination structure into a keto-form anthraquinone-based covalent organic framework (KfAQ), developing the highly efficient KfAQ-Pd single-atom catalyst. Under visible light irradiation, the catalyst demonstrated remarkable efficiency in producing H2O2 from water and oxygen, achieving an impressive generation rate of 3828 μmol h−1 g−1.
Mechanistic investigations revealed that the Pd d orbitals in the Pd–CNO2 unit strongly interact with the p orbitals of oxygen atoms in water molecules. This coupling significantly enhances the adsorption of interfacial water and weakens the O–H bonds, thereby substantially lowering the energy barrier for water dehydrogenation. As a result, the subsequent H2O2 photosynthesis process is greatly accelerated.
By applying this innovative approach, the researchers achieved precise control over the adsorption behavior of interfacial water molecules on the KfAQ material. This advancement successfully overcomes the kinetic limitation of the hydrogen extraction step in the aqueous phase, reinforces the 4e− water oxidation reaction (WOR), and enables highly efficient and stable H2O2 production.
This work not only presents a new pathway to reduce the energy barrier for hydrogen extraction from water molecules but also offers valuable theoretical insights and a practical material platform for designing high-performance photocatalytic systems, demonstrating great potential for the green synthesis of H2O2 using only water and oxygen as feedstocks.