A biomimetic photoredox anthraquinone platform for efficient hydrogen peroxide production

Abstract

Hydrogen peroxide (H₂O₂) is an exemplary green oxidant; however, its commercial synthesis is predominantly restricted by the energy-intensive anthraquinone process, which relies on hydrogen gas and noble metals. Inspired by the flavoenzyme-mediated electron–proton transfer, we designed a biomimetic photoredox anthraquinone platform incorporating hydrazobenzene as a flavin counterpart for solid hydrogen storage mediators, which facilitates the creation of hydrogen peroxide (H₂O₂) without hydrogen gas and metals under mild conditions. After photoexcitation, anthraquinone promotes hydrogen atom transfer from hydrazobenzene, resulting in the generation of azobenzene radicals and anthraquinone hydride, which further interacts with O₂ to produce H₂O₂ while recovering the redox partners in a perpetual cycle. Mechanistic investigations support a radical-mediated, photoinduced electron transfer mechanism. This approach exhibits exceptional H₂O₂ production rates (up to 97 500 μmol g⁻¹ h⁻¹), much higher than state-of-the-art photocatalytic systems, along with broad substrate tolerance, reversible redox cycling, efficient scalability, exceptional bacterial disinfection and adaptable selective oxidation of benzyl alcohol. This study develops a hydrogen-free, bioinspired redox platform that combines enzyme-like efficiency with chemical practicality for sustainable, high-performance H₂O₂ synthesis.