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A novel SrWO 4 /g-C 3 N 4 heterojunction was formed by simple one-pot calcination process and the wide-band gap semiconductor SrWO 4 was in-situ formed on g-C 3 N 4. The prepared photocatalysts were characterized by X-ray diffraction, Scanning Electron Microscopy, Transmission Electron Microscope, Fourier transform infrared spectroscopy, UV–vis diffuse reflectance spectra and Photoluminescence Spectroscopy to investigate the structures, morphology and optical properties of the synthesized materials. The results revealed that SrWO 4 nanoparticles were uniformly distributed on the surface or inside of g-C 3 N 4 to form a compact heterostructure and improved the photocatalytic performance of the material. The binary heterojunction showed better photodegradation efficiency of tetracycline (TC) than pure g-C 3 N 4 and SrWO 4. 88.57% of TC could be degraded by 8% SrWO 4 /g-C 3 N 4 in 2 h under the best experimental conditions. The pH value had little influence on the degradation effect, and the TC degradation rate under strong acid reached 93.94%. In addition, 77.42% TC was still degraded after the fourth cycle. It was concluded that the enhancement of photocatalytic activity due to the inhibition of electrical charge recombination and the improved light absorption capacity. Finally, free radicals capture experiment proved that·O 2 - was the most important active factor of TC degradation, and the possible photocatalytic mechanism was proposed. Schematic diagram of photo-generated electron transfer mechanism of TC degradation by SW/CN under the visible light. [Display omitted] • A novel in-situ visible light-driven SrWO 4 /g-C 3 N 4 nanocomposite photocatalyst prepared by one-pot calcination. • The tetracycline degradation performance of binary heterojunction is stronger than that of pure g-C 3 N 4 by loading SrWO 4. • A special e- one-way transfer mechanism and ·O 2 - account for the enhanced photocatalytic activity. [ABSTRACT FROM AUTHOR]

A novel and efficient ternary composite AgCl/Bi 12 O 15 Cl 6 /g-C 3 N 4 photocatalyst was prepared by co-precipitation method. The physical structure and photochemical properties of the photocatalyst were analyzed by X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Ultraviolet diffuse reflectance spectroscopy (UV-DRS), Fluorescence spectroscopy (PL). The performance of the prepared photocatalysts was evaluated by performing degradation experiments of tetracycline (TC) under different conditions (doping ratio, dosage, initial concentration and initial pH of solution). Furthermore, the stability of composite was confirmed by cycling experiment. Finally, the mechanism of ternary composite AgCl/Bi 12 O 15 Cl 6 /g-C 3 N 4 photocatalyst for decomposition of TC in visible light was investigated by free radical capture experiment. The photoluminescence spectra showed that the peak intensity of the AgCl/Bi 12 O 15 Cl 6 /g-C 3 N 4 composite was significantly reduced compared to other materials, indicating that the photogenerated electron-hole pairs were effectively separated, which contributed to its photocatalytic activity. The composite showed higher TC degradation activity compared to g-C 3 N 4 , Bi 12 O 15 C l6 /g-C 3 N 4 and AgCl/g-C 3 N 4 , with optimum degradation rate constants of 8.2, 2.2 and 1.6 times that of g-C 3 N 4 , Bi 12 O 15 C l6 /g-C 3 N 4 and AgCl/g-C 3 N 4 , respectively. Furthermore, based on the free radical capture experiment, it was confirmed that the active species playing a major role in the reaction process were·O 2 -, followed by h+ and·OH. A double electron transfer mechanism was inferred to be formed in the AgCl/Bi 12 O 15 Cl 6 /g-C 3 N 4 composite and a possible pathway for the degradation of TC was postulated. This work provides a new approach for the effective use of solar energy, as well as a new solution strategy for the degradation of TC in wastewater. [Display omitted] The proposed photocatalytic mechanism for photocatalytic degradation of TC on AgCl/ Bi 12 O 15 Cl 6 /g-C 3 N 4. • The AgCl/Bi 12 O 15 Cl 6 /g-C 3 N 4 exhibited excellent photodegradation of tetracycline (TC) compared to the monomer. • A possible electron transfer mechanism was proposed. • The two-electron transfer mechanism promoted the separation of photogenerated electron-hole pairs in complexes. • Superoxide radical (·O 2 -) was the main reactants in photodegradation, followed by h+ and·OH. [ABSTRACT FROM AUTHOR]