Realizing the synergistic effect of electronic modulation over graphitic carbon nitride for highly efficient photodegradation of bisphenol A and 2-mercaptobenzothiazole: Mechanism, degradation pathway and density functional theory calculation

Here, we successfully synthesized a brown carbon nitride (CY-C3N4) co-modified with oxygen bridge and porous defects via a universal acylation method. Excitingly, density functional theory (DFT) calculation shows that the introduction of oxygen bridges in the calcination polymerization process can adjust the electronic structure and energy band position of the new material. Further, the results of elemental analysis and X-ray photoemission spectroscopy test indicate that the oxygen bridge structure was successfully introduced into the skeleton of carbon nitride. The results show that 0.1CY-C3N4 can remove bisphenol A (BPA) and 2-mercaptobenzothiazole (MBT) with a removal rate of approximately 99% in 90 min and 20 min, respectively. Its degradation rate is 17.94 times and 3.85 times faster than that the original carbon nitride, respectively. Further, through HPLC-MS analysis, the intermediate products of the reaction process were analyzed in depth to propose a possible photocatalytic degradation route. Free radical capturing test and ESR spectroscopy indicate that the formative hydroxyl radical ((OH)-O-center dot), superoxide radical (O-center dot(2)-), singlet oxygen (O-1(2)) and hole (h(+)) all play a key role in the photodegradation. This study provides a new way to synthesize brown carbon nitrides with oxygen bridges and porous defects for environmental applications. (C) 2020 Elsevier Inc. All rights reserved.

Automated summary

In this study, a brown carbon nitride co-modified with oxygen bridges and porous defects was successfully synthesized via a universal acylation method. Results showed that the material had a significantly higher removal rate for bisphenol A and 2-mercaptobenzothiazole compared to the original carbon nitride. Further analysis revealed a potential photocatalytic degradation pathway with key factors including hydroxyl radicals, superoxide radicals, singlet oxygen, and holes.