A novel binary visible-light-driven photocatalyst type-I CdIn2S4/g-C3N4 heterojunctions coupling with H2O2: Synthesis, characterization, photocatalytic activity for Reactive Blue 19 degradation and mechanism analysis

A visible-light-driven photocatalyst CdIn2S4/g-C3N4 was firstly synthesized via a facile and green wet-impregnation method. The crystal phases, particle morphologies, chemical structures and optical properties of the prepared pure g-C3N4, bare CdIn(2)S(4 )and binary CdIn2S4/g-C3N4 heterojunctions were measured in detail by various standard characterization techniques, such as XRD, SEM, TEM, FT-IR, DRS, and PL. And then, a novel and high-efficiency visible-light-driven photocatalytic system comprised of binary CdIn2S4/g-C3N4 heterojunctions and H2O2 has been successfully constructed and exhibited superior photocatalytic degradation of Reactive Blue 19 (RB19). The following results can be obtained by photochemical characterizations and photocatalysis experiments: Compared with the pristine g-C3N4, the addition of CdIn2S4 to form a type-I CdIn2S4/g-C3N4 heterojunction effectively increases the visible light absorption range and reduces the recombination rate of photogenerated electron-hole pairs. After 100 min visible light irradiation, the photocatalytic degradation rate of RB19 by CdIn2S4/g-C3N4 was approximately 8.30 times and 2.68 times higher than that of monomer g-C3N4 and CdIn2S4, respectively. After 60 min visible light irradiation, the photodegradation efficiency of the novel photocatalytic system (CdIn2S4/g-C3N4 and H2O2) is 1.99 times higher than that of CdIn2S4/g-C3N4 for RB19. Furthermore, the photocatalytic mechanism of the novel visible-light-driven photocatalytic system was proposed and elaborated. These findings emphasize the main role of g-C3N4 in the degradation of organic dyes and provide a reasonable and effective method for rational design of a high-efficiency and low-cost visible light-driven photocatalytic system.