Enhanced photocatalytic efficiency of TiO2/CdS nanocomposites by manipulating CdS suspension on TiO2 nanoparticles

Titanium Dioxide (TiO2) has long been found to be a promising photocatalyst in the ultraviolet region, although it faces several limitations in the visible range. Various attempts for overcoming these shortcomings have shown that TiO2 nanocomposites offer excellent results for visible area photocatalysis. In the present work, three different samples of TiO2/CdS nanocomposites are synthesized using simple and cost-effective hydrothermal method, based on different concentrations of cadmium and sulphur precursors and a comparison is made among them. Characterization techniques like Scanning Electron Microscopy (SEM), Photoluminescence (PL) spec-troscopy, UV-visible spectroscopy, X-ray Diffraction (XRD), Energy Dispersive X-ray Analysis (EDX) and Fourier Transform Infrared (FTIR) spectroscopy are employed to study morphological, optical, structural, and elemental properties of the as-synthesized nanocomposites. SEM analysis shows that change in concentration of precursors caused morphological changes in the resulting samples. XRD characterization shows that the crystallite size gets modified at different concentrations ranging from approximately 21 nm to 5 nm. As per the UV-vis spectroscopy, the band gap of TiO2/CdS nanocomposites has substantially decreased, making it highly suitable for photo-catalytic application in the visible region in comparison to pure TiO2. Photocatalytic degradation processes for as-synthesized TiO2/CdS nanocomposites are studied for methylene blue (MB) and rhodamine B (RhB) dyes under visible light exposure. Results demonstrate that degradation results for MB dye are better in comparison to RhB dye for all the three synthesized photocatalysts. Futher, it is concluded that TiO2/CdS nanocomposite with a 1:1 M ratio of cadmium and sulphur precursors has the optimum photocatalytic performance for dye degradation.

Automated summary

This study focuses on the synthesis of TiO2/CdS nanocomposites with different concentrations of precursors and their characterization using various techniques. The results show that TiO2/CdS nanocomposites exhibit excellent photocatalytic performance in the visible range compared to pure TiO2, and they have better degradation efficiency for methylene blue dye compared to rhodamine B dye. The optimum photocatalytic performance is achieved with a 1:1 M ratio of cadmium and sulphur precursors.