Vacancy-Induced Surface Oxygen Doping Synergistically Enhances Electron Migration at Carbon-Nitride Interfaces: Coupling Dft Simulations with Experiments

Abstract

Oxygen-doped carbon nitride (O-Nv-CN) with nitrogen vacancy was prepared by a two-step calcination method. Due to its apparent electronicity, the composite is easily protonated and attracts photogenerated holes, which facilitates carrier separation. The photocatalytic degradation performance of tetracycline hydrochloride (TC-HCl) was good over the whole pH range and in the presence of interfering ions. Compared with the original bulk g-C3N4, there are a certain number of mesoporous pores in the composite structure, which increases the specific surface area of the catalyst, and the TC-HCl degradation rate of modified O-NV-CN is 4.5 times that of pure phase g-C3N4, and the electron transfer rate of O-NV-CN is accelerated under the interaction of N-vacancy and O element. O-Nv-CN also shows good stability and reproducibility. In addition, the binding energy of O2 and H2O of the composite was calculated by density functional theory, and the results showed that the electrons in O-Nv-CN were more likely to react with the surrounding O2 to produce ·O2-, and the trapping experiment and ESR detection also indicated that ·O2- was the main active substance. In conclusion, this study provides a new way to investigate the photocatalytic degradation of antibiotics.

Keywords: photocatalysis, Tetracycline, Nitrogen vacancy, Oxygen doping, Density Functional Theory