In-situ generated SrWO4/g-C3N4 heterojunction photocatalyst for enhanced visible light degradation activity of tetracycline

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. • 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.