Conjugated Organic Polymers with Anthraquinone Redox Centers for Efficient Photocatalytic Hydrogen Peroxide Production from Water and Oxygen under Visible Light Irradiation without Any Additives

The photocatalytic generation of hydrogen peroxide (H2O2) from H2O and O2 under visible light irradiation is a hopeful approach to achieve solar-to-chemical energy transformation. While the lack of specific redox reaction centers is still the main reason for low photocatalytic H2O2 production efficiency, herein, we present a conjugated organic polymer (AQTEE-COP) containing anthraquinone redox centers by Sonogashira cross-coupling reaction between 2,6-dibromoanthraquinone (AQ) and 1,1,2,2-tetrakis(4-ethynylphenyl)ethene. The extended π-conjugated framework with an electron push–pull effect between electron-donating tetraphenylethene moieties and electron-withdrawing anthraquinone moieties not only broadened the visible light absorption range but also promoted the separation and migration of photo-induced charge carriers. Meanwhile, the anthraquinone moieties can serve as redox centers to accept photo-induced electrons and transfer them to adsorbed O2 molecules for subsequent H2O2 production. The well-defined structure of AQTEE-COP with task-specific anthracene redox centers provides molecular-level insights into the mechanistic understanding of the photocatalytic H2O2 generation from H2O and O2. The AQTEE-COP exhibits efficient photocatalytic H2O2 production with an initial rate of 3204 μmol g–1 h–1 under visible light (λ ≥ 400 nm) irradiation without any additional photosensitizers, organic scavengers, or co-catalysts. This article provides a protocol for the rational design of pre-functionalized conjugated organic polymer-based materials for solar-to-chemical energy transformation.