Synergically integrating carbon-vacancy defected carbon nitride with anthraquinone for boosted photocatalytic H2O2 production

A novel all-organic AQ/CvCN photocatalyst is designed for H₂O₂ photosynthesis. • The optimal 20% AQ/C V CN shows 18-fold H₂O₂ photosynthesis activity over pristine CN. • The synergy of AQ/C V CN promotes charge transfer and O₂ adsorption-activation. • AQ/CvCN maintains stable H₂O₂ production activity after long-term cycling tests. Carbon nitrides (CN) have been extensively studied in hydrogen peroxide (H 2 O 2 ) photosynthesis research field owing to their remarkable stability and tunable structural properties. Nevertheless, the weak photogenerated carrier separation ability, the insufficient adsorption and activation of O 2 , and the high reduction potential for H 2 O 2 generation on CN limit their applications in photocatalytic H 2 O 2 production. Herein, we successfully prepared all-organic CN-based photocatalysts (AQ/CvCN) via combining CN with carbon vacancies (Cv) and anthraquinone (AQ) to overcome the above limitations, thereby enhancing photocatalytic H 2 O 2 production. Significantly, experimental results and theoretical calculations demonstrate that the introduced Cv can break the symmetrical structure of CN and act as electron capture sites, which remarkably enhances the photogenerated carrier separation and the adsorption and activation of O 2 , while the loading of AQ can optimize the reduction potential of O 2 to H 2 O 2 and reduce the formation energy barrier of the critical intermediate *OOH, therefore collaboratively improving the activity of photocatalytic H 2 O 2 production. The designed 20% AQ/CvCN catalyst achieved a photocatalytic H 2 O 2 production rate of 10,053.46 μmol g −1  h −1 , which is 18.16 and 5.58 times higher than that of CN and CvCN, respectively. In addition, 20% AQ/CvCN maintains stable H₂O₂ evolution activity after long-term cycling tests. This study provides an efficient, economical, and environmentally friendly approach for designing CN-based photocatalysts used in photocatalytic H 2 O 2 production. Download: Download high-res image (367KB) Download: Download full-size image