Synergistic enhancement of photocatalytic degradation of dyes by structural defects and silver nanoparticles.

The AgNPs@NCN composite was prepared by loading silver nanoparticles (AgNPs) onto the surface of carbon nitride (g-C 3 N 4) with nitrogen-vacancy and cyanide defect and used for the synergistic degradation of methylene blue (MB) by the structural defect of g-C 3 N 4 , the surface plasmon resonance of AgNPs and Schottky barrier formed between them. The morphology, structure, chemical composition and photoelectrochemical properties were characterized by SEM, TEM, FTIR, XRD, XPS, BET and UV–Vis. The effects of different loads of AgNPs on photocatalytic performance were investigated and the results showed 10%AgNPs@NCN exhibited good photodegradation performance. The maximum degradation efficiency of MB by 10%AgNPs@NCN reached 100% with the rate constant of 0.05443 min−1, which was 9.15 and 6.89 times higher than those of g-C 3 N 4 (0.00595 min−1) and NCN (0.0079 min−1), respectively. The mineralization degree of organic pollutants was evaluated by total organic carbon (TOC) and the results showed that the TOC removals of 10%AgNPs@NCN photocatalytic reaction were 77% and 93% for MB and wastewater, respectively. After four cycles of photocatalytic degradation experiments, the degradation rate of MB was still more than 98.2% and there was no significant change in the characteristic stretching of the catalyst, indicating that the prepared photocatalyst had good stability and reusability. Synergistic degradation of MB based on AgNPs@NCN. Due to the synergistic effect of the nitrogen-vacancy and cyanogen defect of NCN, the surface plasmon resonance of AgNPs and Schottky barrier formed between them, the effective degradation of methylene blue (MB) by AgNPs@NCN composite under visible light irradiation is realized. Under simulated sunlight irradiation, AgNPs@NCN photocatalyst could degrade 100% MB in the solution in 60 min, and the degradation rate was 15.3 and 11.5 times that of g-C 3 N 4 and NCN. [Display omitted] • AgNPs@NCN was prepared by depositing AgNPs on g-C 3 N 4 with structural defect. • The synergistic degradation of MB is realized by structural defect, AgNPs and Schottky barrier. • Under simulated sunlight irradiation, AgNPs@NCN could degrade 100% MB in 60 min. • The proposed method based on the AgNPs@NCN for degrading MB showed high stability. [ABSTRACT FROM AUTHOR]