Modulation of Polymer Catalysts by an Amino Side-Chain Structure for Hydrogen Peroxide Photosynthesis

The synthesis of hydrogen peroxide (H2O2) via photocatalysis is an environmentally sustainable strategy. Despite this, the development of efficient, stable, and low-cost photocatalysts presents ongoing challenges. Polymer photocatalysts, known for their low cost, low toxicity, and tunable structures, often suffer from limited visible light absorption, poor electron transfer efficiency, and weak water affinity. To address these limitations, we integrated amino molecules with different structures into polyphenolic dye procyanidins to synthesize conjugated polymer photocatalysts with a broad spectral absorption range from 200 to 1100 nm for H2O2 photogeneration. Notably, the proanthocyanidin-based catalyst with a linear amino structure showed a H2O2 yield of 1618 μmol g–1 h–1 in air, surpassing the performance of other structurally similar catalysts. The study reveals that the spatial configuration of amino units plays a critical role in the polymer’s hydrogen bonding with water and the migration of photogenerated carriers. Linear amino unit arrangements interact more effectively with water molecules, enhancing catalyst surface water adsorption and facilitating charge separation and transfer. This work paves the way for the molecular-level engineering of efficient polymeric photocatalysts for artificial photosynthesis.