SnS thin films deposited at room temperature - Efficient and reusable dark catalyst for water remediation at ambient conditions

This study describes the dark catalytic degradation of cationic, anionic, and commercial dyes by SnS thin films under dark ambient conditions without the assistance of any external stimuli. The thin films were deposited by a modified SILAR (Successive Ionic Layer Adsorption and Reaction) method at room temperature and characterised using XRD, XPS, FESEM, TGA, and UV-visible spectrophotometers. The dark catalytic degradation of methylene blue (MB) dye was investigated using a spectrophotometer and validated by LCMS analysis and an adsorption desorption test. Within 15 min, 48 % of the MB dye (original concentration: 10 mg/l) had been degraded by the catalyst, and by 90 min, the degeneration was almost complete. The ROS (reactive oxygen species) scavenger test and indicator test confirmed the role of the hydroxyl radical in the degradation process. The influence of initial dye concentration, magnetic stirring, and the composition of the catalyst on the degradation efficiency was also studied. The same catalyst was used five times in succession to test its reusability, and it was then structurally and thermally characterised to test its stability. This study emphasises the possible use of SnS thin film as an effective, reliable, and reusable around-the-clock catalyst for the degradation of dyecontaminated waste water without the assistance of light or any chemical additives.