Anthraquinone-Based Metal–Organic Framework with Proton Transfer for Enhanced H ₂ O ₂ Photosynthesis

Photocatalytic oxygen reduction offers a green route to hydrogen peroxide (H₂O₂) production, yet practical efficiency is often limited by insufficient visible-light harvesting, fast charge recombination, and the kinetic mismatch between proton supply and interfacial electron transfer. Inspired by the industrial anthraquinone (AQ) redox cycle, we report the in situ embedding of an anthraquinone unit into a zirconium-based metal-organic framework (Zr-AQ-MOF) to create a highly efficient and stable photocatalyst for H₂O₂ synthesis. Comprehensive characterization reveals that the AQ centers extend light absorption, provide abundant active sites, promote charge separation and transport, and facilitate a two-electron oxygen reduction pathway via superoxide radicals (•O₂⁻), significantly enhancing the H₂O₂ production efficiency. Notably, 2-propanol functions as both a hole scavenger and a proton source, promoting rapid proton delivery to AQ centers and enabling a proton-coupled electron transfer that suppresses charge recombination and accelerates H₂O₂ formation. Furthermore, Zr-AQ-MOF exhibits excellent broad-spectrum antibacterial activity of both E. coli and S. aureus under light irradiation, highlighting its potential for integrated H₂O₂ generation and water purification.