Sulfur/Gadolinium‐Codoped TiO₂ Nanoparticles for Enhanced Visible‐Light Photocatalytic Performance

Abstract

A series of S/Gd 3+ ‐codoped TiO 2 photocatalysts were synthesized by a modified sol‐gel method. The materials were characterized by X‐ray diffraction (XRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), UV‐visible diffuse reflectance spectroscopy, scanning electron microscopy (SEM)/energy‐dispersive X‐ray spectroscopy (EDX), and transmission electron microscopy (TEM)/energy‐dispersive spectroscopy (EDS). Laboratory experiments with Indigo Carmine chosen as a model for organic pollutants were used to evaluate the photocatalytic performance of S/Gd 3+ ‐codoped TiO 2 under visible‐light with varying concentrations of Gd 3+ ions in the host material. XRD and Raman results confirmed the existence of anatase phase TiO 2 with particle size ranging from 5 to 12 nm. Codoping has exerted a great influence on the optical responses along with red shift in the absorption edge. S/Gd 3+ ‐codoped TiO 2 showed significant visible‐light induced photocatalytic activity towards Indigo Carmine dye compared with S‐TiO 2 or commercial TiO 2 . TiO 2 ‐S/Gd 3+ (0.6% Gd 3+ ) degraded the dye ( k a = 5.6 × 10 −2 min −1 ) completely in 50 min.