Site engineering of linear conjugated polymers to regulate oxygen adsorption affinity for boosting photocatalytic...

Artificial photosynthesis of hydrogen peroxide (H₂O₂) is a hopeful alternative to the industrial anthraquinone process. However, rational fabrication of the photocatalysts for the production of H₂O₂ without any sacrificial agents is still a formidable challenge. Herein, two kinds of linear conjugated polymers (LCPs) including pyridinic N functionalized polymer (DEB-N₂) and pyridinic N non-contained polymer (DEB-N₀) were successfully synthesized. DEB-N₂ displays enhanced light capturing ability and good dispersion in water, leading to a substantial initial H₂O₂ generation rate of 3492μmol g^-1h^-1 as well as remarkable photocatalytic stability in pure water. Furthermore, the temperature programmed desorption (TPD) and density functional theory (DFT) analysis reveal that highly electronegative pyridine-N atoms in DEB-N₂ boost the adsorption affinity of oxygen molecules, which facilitates the occurrence of the oxygen reduction reaction, therefore enhancing the performance of photocatalytic H₂O₂ production. This study unveils that the presence of pyridinic N in DEB-N₂ has a significant impact on photocatalytic H₂O₂ production, suggesting the precise manipulation of the chemical structure of polymer photocatalysts is essential to achieve efficient solar-to-chemical energy conversion.