Enhanced separation performance of g-C3N4/Ag3PO4 heterojunction photocatalyst for efficient degradation of methylene blue and bisphenol A

Type II g-C3N4/Ag3PO4 photocatalysts were prepared by an in situ chemical precipitation method used to investigate the photocatalytic degradation performance. In this work, the g-C3N4/Ag3PO4(1:1) composite catalyst exhibited superior photocatalytic performance for MB and BPA degradation, the degradation rate of MB reached 100 % within 80 min, and the degradation rate of BPA reached 98.5 % within 100 min, which were 1.8 and 8.7 times higher than that of g-C3N4, respectively. Its reaction rate abided by the pseudo-first-order kinetics, kinetic rate constants (kappa) were 0.0626 min(-1) and 0.0419 min(-1), respectively. Through a series of characterizations, it was found that the intimate interface contact between g-C3N4 and Ag3PO4 formed type II heterojunction, not only shortening photogenerated carriers transfer distance and accelerating the separation of photogenerated carriers, but also enhancing the stability and reusability of the g-C3N4/Ag3PO4 composite catalyst. Meanwhile, the h(+) radicals and center dot O-2(-) radicals were main active species of photocatalytic degradation reactions by the free radical trapping experiments and ESR tests further were confirmation. A possible photocatalytic mechanism was studied by UV-vis DRS, Mott-Schottky curves, the free radical trapping experiment and ESR. This aim of this paper is to improve the efficiency of photocatalytic degradation of MB and BPA by synthesizing type II g-C3N4/Ag3PO4 photocatalysts.