Functional Groups-Regulated Organic Semiconductors for Efficient Artificial Photosynthesis of Hydrogen Peroxide

Hydrogen peroxide (H₂O₂) is an environmentally friendly reagent, and organic semiconductors (OSCs) are ideal photocatalysts for the synthesis of H₂O₂ due to their well-defined molecular structure, strong donor-acceptor interactions, and efficient charge separation. This review discusses the regulatory mechanisms of functional group modifications in tuning the photocatalytic performance of OSCs, highlighting the relationship between functional group structure and catalytic performance. For example, electron-regulating groups, such as cyano and halogen, induce molecular dipoles, facilitating the migration of photogenerated electrons. Fluorine groups optimize the band structure and prolong carrier lifetime due to their high electronegativity. π-Conjugated extension groups, like anthraquinone and thiophene, expand conjugation, improve visible light capture, and stabilize intermediates through redox cycles. Hydroxyl groups enhance surface hydrophilicity and promote H₂O activation, while imine bond protonation adjusts charge distribution and improves selectivity and cycle stability. Multi-active site functional groups, such as sulfonic acid and amide, accelerate reaction kinetics and inhibit H₂O₂ decomposition. Functional groups enhance light absorption, charge separation, and surface reactions through electronic structure regulation, intermediate adsorption optimization, and proton-electron transfer. Future work should integrate machine learning to identify optimal functional group combinations and develop green functionalization strategies for efficient H₂O₂ photocatalyst synthesis.