Synthesis of gadolinium-doped TiO2 thin films by sol-gel spin coating technique and its application in degradation of rhodamine-B

In this research, a sol-gel spin coating method was employed to prepare pure arid gadolinium (Gd)-doped TiO2 thin films on microscopic glass slides. The structure and morphology of prepared thin films were characterised by X-ray diffraction (XRD), scanning electron microscope (SEM) equipped with energy-dispersive X-ray analyser, UV-VIS absorption spectroscopy, atomic force microscope and Brunauer-Emmett-Teller (BET) surface area techniques. The sol-gel-fabricated thin films were employed for degradation of Rhodamine-B (RhB) dye under UV light irradiation. XRD results revealed that the synthesised films were crystalline and in anatase phase. The blue shift in the absorption spectra was observed with increase in Gd concentration up to 4 wt%. The BET surface area of doped films was more compared to pure TiO2 films. The amount of Gd3+ had a great impact on the photocatalytic activity of TiO2 films and Gd-TiO2 (4 wt%) films exhibited the optimal photocatalytic degradation. About 99% of RhB degradation was observed within 50 min of UV irradiation. The effect of the addition of inorganic anions and electron acceptors on degradation was also studied. The sol-gel-synthesised Gd-TiO2 films can be used as an effective catalyst for degradation of various other organic compounds under UV light irradiation.