Site engineering of linear conjugated polymers to regulate oxygen adsorption affinity for boosting photocatalytic production of hydrogen peroxide without sacrificial agent

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 3492 mu mol 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 photo- catalytic 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.