Fabrication of g-C3N4/SnS2/SnO2 nanocomposites for promoting photocatalytic reduction of aqueous Cr(VI) under visible light

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 335; pp. 491 - 500
• Main Authors: Yang, Yue, Yang, Xin-An, Leng, Di, Wang, Shang-Bing, Zhang, Wang-Bing
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.03.2018
• Subjects: g-C3N4/SnS2/SnO2; Heavy metal ions; Photocatalytic reduction; Ultrasonic irradiation; Washing regeneration; Heavy metal ions; Washing regeneration; Ultrasonic irradiation; Photocatalytic reduction; g-C3N4/SnS2/SnO2
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2017.10.173

[Display omitted] •g-C3N4/SnS2/SnO2 nanocomposites were firstly fabricated by solvothermal method after 30 min ultrasonic irradiation.•Reaction rate constant of Cr(VI) can be improved 41.7- and 4.0-time, compared with pure g-C3N4 and SnS2/SnO2, respectively.•More than 90% lost photocatalytic activity can be regenerated by water-washing. A kind of g-C3N4/SnS2/SnO2 nanocomposite was firstly prepared by solvothermal method at 140 °C for 4 h after 30 min ultrasonic irradiation. X-ray photoelectron spectroscopy (XPS), electron spin resonance (ESR), transmission electron microscopy (TEM) and electrical/optical testing techniques confirmed that the oxygen atoms in SnO2 might be doped in the g-C3N4 in the synthesizing process, resulting to a good combination of SnS2/SnO2 nanosheets and g-C3N4 nanoparticles by SnOC bond, which would have an influence on the light adsorption, carriers transfer, and electron-hole separation efficiency of g-C3N4/SnS2/SnO2. Additionally, the ultrasonic assisted solvothermal reaction could also promote the formation of oxygen vacancies on the surface of the material, which leads to the up-shift of valence band. The photocatalytic properties of the g-C3N4/SnS2/SnO2 were studied by the reduction of aqueous Cr(VI). The data clearly indicated that the photocatalytic activity of as-synthesized composites depends on their compositions, and reaction rate constant of Cr(VI) on the composite-C (with the mass ratio of 1:3) with visible light (λ > 420 nm) driven can be improved 41.7- and 4.0-time compared with pure g-C3N4 and SnS2/SnO2, respectively. Additionally, more than 90% lost photocatalytic activity of composite-C can be regenerated by water-washing and drying treatment. The present study provided an efficient method for removing toxic Cr(VI) ions via photoreduction utilizing visible light irradiation (λ > 420 nm).