The construction of an alkynyl-containing porous polymer for enhanced photocatalytic H₂O₂ generation

Organic polymer photocatalysts are a promising material platform for photosynthetic hydrogen peroxide production from water and oxygen. However, limited by the controlled structural design and lack of effective active sites, their photocatalytic efficiency is unsatisfactory. To address these above issues, we precisely designed and prepared two alkyne-based porous polymers via the Sonogashira cross-coupling reaction (POP-DT and POP-DF). Acetylene served as the oxygen-reducing active site, tuning the thiophene or furan ring as the electron donor unit. They exhibited a large specific surface area and rich pore architecture. Under visible light irradiation, the H2O2 generation rate of POP-DT was as high as 2422.2 mu mol g(-1) h(-1), which was 4.3 times higher than that of POP-DF, representing one of the best performances ever reported for polymeric photocatalysts. We found that the combination of acetylene and thiophene resulted in faster charge separation and transfer efficiency, significantly improving the kinetic behaviour of the oxygen reduction reaction. More importantly, combined with in situ diffuse reflectance infrared Fourier transform spectroscopy and theoretical calculations, we demonstrate that acetylene-connected thiophene is more beneficial to the electron enrichment of the acetylene active site, enhancing the adsorption and activation of oxygen, thus boosting the photocatalytic efficiency for the oxygen reduction reaction. Our work provides a novel strategy for designing advanced polymer photocatalysts for enhanced solar energy conversion efficiency.