Hydrothermal synthesis of tin sulfide nanoparticles for improved surface catalytic activity in the degradation of azo dyes
摘要
The surface catalytic activity of highly stable SnS nanoparticles has been analyzed adopting hydrothermal process, utilizing different concentrations of SnCl2 precursor. The SnS nanoparticles displayed orthorhombic crystal structures with plane orientations of (110), (120), (111), (131) and (041) as assessed by powder XRD. The crystallite size is found to increase as the SnCl2 precursor concentration was increased. The vibrational assignments pertaining to SnS has been analyzed using FTIR spectrum. All nanoparticles exhibited broad optical absorption in the visible range and their bandgaps have been reported. The surface area of the SnS nanoparticles was 35.26 m2/g at a low SnCl2 concentration (0.1 M) and increased to 68.78 m2/g at a higher SnCl2 concentration (0.6 M). The XPS analysis confirms the presence of Sn2⁺ metallic phase. These SnS catalysts were employed to degrade methyl blue (MB), congo red (CR), and eriochrome black T (EBT) azo dyes in aqueous solutions under dark moiety, without the use of additional reagents or energy. The SnS catalyst prepared with 0.6 M SnCl2 concentration showed a 63% degradation efficiency in 60 min, outperforming the 33% efficiency of the SnS catalyst synthesized with 0.4 M SnCl2 and the 4% efficiency of the catalyst with 0.1 M SnCl2. The high dye degradation was primarily due to the surface catalytic properties of the SnS nanoparticles, which generate electrons upon interacting with the dye molecules, leading to the breakdown of azo bonds. Under visible light irradiation, the SnS catalyst achieved a 90% degradation efficiency for methyl blue dye in 60 min. Additionally, the catalyst demonstrated excellent stability and reusability through multiple cycles, as verified by XRD and XPS analysis of the catalyst before and after reuse.