Hydrogen peroxide (H2O2) has received increasing attention because it is not only a mild and environmentally friendly oxidant for organic synthesis and environmental remediation but also a promising new liquid fuel. The production of H2O2 by photocatalysis is a sustainable process, since it uses water and oxygen as the source materials and solar light as the energy. Encouraging processes have been developed in the last decade for the photocatalytic production of H2O2. In this Review we summarize research progress in the development of processes for the photocatalytic production of H2O2. After a brief introduction emphasizing the superiorities of the photocatalytic generation of H2O2, the basic principles of establishing an efficient photocatalytic system for generating H2O2 are discussed, highlighting the advanced photocatalysts used. This Review is concluded by a brief summary and outlook for future advances in this emerging research field.

The synthesis of hydrogen peroxide (H2O2) from H2O and O2 by metal-free photocatalysts (e.g., graphitic carbon nitride, C3N4) is a potentially promising approach to generate H2O2. However, the photocatalytic H2O2 generation activity of the pristine C3N4 in pure H2O is poor due to unpropitious rapid charge recombination and unfavorable selectivity. Herein, we report a facile method to boost the photocatalytic H2O2 production by grafting cationic polyethylenimine (PEI) molecules onto C3N4. Experimental results and density functional theory (DFT) calculations demonstrate PEI can tune the local electronic environment of C3N4. The unique intermolecular electronic interaction in PEI/C3N4 not only improves the electron–hole separation but also promotes the two-electron O2 reduction to H2O2 via the sequential two-step single-electron reduction route. With the synergy of improved charge separation and high selectivity of two-electron O2 reduction, PEI/C3N4 exhibits an unexpectedly high H2O2 generation activity of 208.1 μmol g–1 h–1, which is 25-fold higher than that of pristine C3N4. This study establishes a paradigm of tuning the electronic property of C3N4 via functional molecules for boosted photocatalysis activity and selectivity.

Hydrogen peroxide (H2O2) is a commodity chemical applied in diversified products and industries. Nevertheless, its current industrial production process is not sustainable. Photoredox catalysis over semiconductors is a very promising...

Nanomaterials open an alternative way for water disinfection. However, limitations such as aggregation, toxicity, and complex post‐treatment block their practical application. In this study, an antibacterial silver/reduced graphene oxide (Ag/rGO) hydrogel consisting of controlled porous rGO network and well‐dispersed Ag nanoparticle is synthesized by a facile hydrothermal reaction. Scanning electron microscopy, transmission electron microscope, X‐ray diffraction, mercury porosimetry, and Fourier transform IR spectroscopy are employed to characterize the Ag/rGO hydrogel. The 3D structure of the rGO network serves as an excellent support for Ag nanoparticles. Disinfection experiments show that the Ag/rGO hydrogel exhibits good efficacy against Escherichia coli when used as a bactericidal filter driven by gravity. The mechanistic study indicates that bacteria cells are inactivated due to cell membrane damage induced by silver nanoparticles and rGO nanosheets when they flow through Ag/rGO hydrogel. Moreover, due to the retaining of Ag by rGO, the leaching level of silver from Ag/rGO hydrogel is considerably lower than the drinking water standard. This study sheds new light on designing antibacterial materials for point‐of‐use water disinfection application.

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