Enhanced UV light-driven photocatalytic degradation of methyl orange using MoO3/WO3-fluorinated TiO2 nanocomposites

Abstract

TiO2-based heterogeneous photocatalysis destroys persistent organic pollutants (POPs) with a low-cost, environment-friendly alternative to the conventional method. In the current research, TiO2, TiO2-F, TiO2-F-MoO3, TiO2-F-WO3, and TiO2-F-MoO3-WO3 nano-photocatalysts were synthesized via the sol-gel route, and their photocatalytic performances were investigated for the removal of methyl orange (MO) dye in the presence of ultraviolet (UV) light in a suspension configuration. X-ray diffraction (XRD), Scanning electron microscope (SEM), Fourier-transform infrared spectroscopy (FTIR), UV–vis diffuse reflectance spectroscopy (UV–vis/DRS), and Brunauer-Emmett-Teller (BET) characterized structural, morphological, and optical properties. XRD analysis showed that the prepared catalyst was mainly anatase with a 6.29 to 17.54 nm crystal size. SEM and FTIR analysis confirmed the irregular morphologywith agglomerated particle size of 13.31 ± 2.55 nm and hydroxyl groups captured by water molecules. BET isotherms revealed five times higher surface area and pore volume in doped nanocomposites than undoped TiO2 nanoparticles (NPs). The light-absorption properties of TiO2 NPs were significantly increased by fluorine doping and subsequent coupling with WO3. The reason can be explained by increased visible light harvesting and photogenerated charge carrier recombination reduction. The highest photodegradation efficiency was found to be 99.68 % for TiO2-F-WO3 nanocomposites for MO dye (10 ppm). The best-fitted reaction rate constants were followed by the pseudo-second-order model and found to be 16.1×10−4 g.mg−1.min−1 for TiO2-F-WO3 nanocomposite. Overall, TiO2-F-WO3 can be considered a promising material for photocatalytic POPsdegradation in textile wastewater.