Preparation of g-C3N4/TiO2/BiVO4 composite and its application in photocatalytic degradation of pollutant from TATB production under visible light irradiation.

A novel and highly efficient ternary mpg-C 3 N 4 /BiVO 4 /TiO 2 composite was successfully synthesized and characterized with regard to structure, chemical composition, optical properties and degradation application. The photocatalytic activities of as-prepared samples were evaluated by the photocatalytic decomposition of methylene blue (MB), practical effluent from alkylation and amination steps in 1,3,5-triamino-2,4,6-trinitrobenzene (TATB) production. Compared with TiO 2 , BiVO 4, and mpg-C 3 N 4 , the binary composites TiO 2 /BiVO 4 and the ternary mpg-C 3 N 4 /BiVO 4 /TiO 2 composites exhibited the higher photocatalytic activity under visible light irradiation. Compared to solo mpg-C 3 N 4 and BiVO 4 , the photocatalytic efficiency of g-C 3 N 4 /TiO 2 /BiVO 4 raised up to 94%. The catalytic activity of g-C 3 N 4 /TiO 2 /BiVO 4 against TATB (alkylation and amination) also confirms its efficiency by creating intermediate which were detected by Q-TOF-MS. The thermal stability and photo-stability of the produced composites were investigated. From the view of practical application, mpg-C 3 N 4 /BiVO 4 /TiO 2 displayed superior photostability after five times recycle. The mechanism research showed the fitting of band structure among BiVO 4 , g-C 3 N 4, and TiO 2 . The presence of mpg-C 3 N 4 and BiVO 4 can notably adjust the band gap energy and the synergy effects of them can prolong the lifetime of the charge carrier. [ABSTRACT FROM AUTHOR]