A novel double Z-scheme photocatalyst Ag3PO4/Bi2S3/Bi2O3 with enhanced visible-light photocatalytic performance for antibiotic degradation

In this study, the novel visible light double Z-scheme photocatalysts (Ag3PO4/Bi2S3/Bi2O3) were synthesized by the facile means. The crystal texture, chemical states, morphology and optical characteristics of prepared photocatalysts were investigated by XRD, FTIR, XPS, SEM, TEM, N-2 adsorption-desorption analysis, UV-vis DRS, and PL etc. techniques, respectively. Meanwhile, the band structures and the density of states of three single-phase semiconductor and Ag3PO4/Bi2S3/Bi2O3 (ABB) composite had been calculated by Materials Studio program based on density functional theory. For assessing the photocatalytic performance of these samples, the visible light photodegradation of antibiotics sulfamethazine (SAZ) and cloxacillin (CLX) were performed. The effects of initial antibiotic concentration, reaction pH, supporting electrolyte and surfactant on photocatalytic performance were all investigated. The results indicated that the ABB-3 composite exhibited higher photocatalytic performance than other comparison samples. Furthermore, four cycle experiments confirmed the ABB-3 composite also exhibited satisfactory photostability. The scavenger tests and ESR data demonstrated that the active species h(+), O-center dot(2)-, and center dot OH worked together in the photocatalytic process, and the h(+) and O-center dot(2)- play a more important role than (OH)-O-center dot. All in all, the increased photocatalytic performance of ABB composite could owe to the photosensitization of Bi2S3 and the double Z-scheme photocatalytic system. This study could inspire some new idea for building the novel and efficient heterogeneous photocatalysts and benefiting their practical application.