Singlet‐Oxygen‐Driven Cooperative Photocatalytic Coupling of Biomass Valorization and Hydrogen Peroxide Production Using Covalent Organic Frameworks

Abstract

Traditional H₂O₂ photocatalysis primarily depends on photoexcited electrons and holes to drive oxygen reduction and water oxidation, respectively. However, singlet oxygen (¹O₂), often underappreciated, plays a pivotal role in H₂O₂ production. Meanwhile, photocatalytic biomass conversion has attracted attention, yet studies combining H₂O₂ synthesis with biomass valorization remain rare and typically yield low-value products. Herein, a strategy of photocatalytic valorization of furfuryl alcohol (FFA) coupled with the efficient co-production of H₂O₂ is reported, enabled by covalent organic frameworks (COFs) induced, ¹O₂-participated Achmatowicz rearrangement. This study introduces polyimide-based COF-N_0-3 with tailored nitrogen content, representing an unprecedently efficient platform for ¹O₂ production. Remarkably, reducing the nitrogen content of the COF enhances ¹O₂ production, significantly boosting the H₂O₂ generation rate. In FFA, the primary pathway for H₂O₂ production is Achmatowicz rearrangement, achieving a rate ten times higher than that reliant on oxygen reduction reaction in pure water, reaching 4549 µmol g⁻¹ h⁻¹. Mechanism studies revealed ¹O₂ selectively engaged FFA, bypassing hole oxidation to trigger the Achmatowicz rearrangement, producing valuable 6-hydroxy-(2H)-pyranone with 99% conversion and 92% selectivity. This work establishes a coupling strategy for simultaneous synthesis of H₂O₂ and biochemicals, offering a transformative approach to sustainable photocatalysis.