Solvothermally synthesized dopant-free anatase-titania nanostructures for efficient photocatalytic degradation of crystal violet under violet irradiation

Abstract

The anatase polymorph of titania is known for its photocatalytic behavior. In this study, titania nanoparticles synthesized through sol-assisted solvothermal process carried out in an autoclave were utilized as photocatalyst under violet radiation for the degradation of a model pollutant, namely crystal violet. The presence of titania in the anatase form was confirmed by x-ray diffraction. Electron microscopy revealed the coexistence of rod-like and spherical-shaped structures in the nano-titania. The average diameters were 9.8 nm and 12 nm for the spherical nanoparticles and the cylindrical ones, respectively. The band gap energy of titania as calculated from the uv–vis spectroscopy was 3.22 eV, which is in line with its theoretical value. The specific surface area of the nano-titania was 39.179 m2/g, and the total pore volume was 0.05 cc/g, which indicates the presence of large number of active sites on the surface of the photocatalyst for the adsorption of pollutant molecules. Excitation and emission spectra of titania were acquired using photoluminescence spectroscopy to ascertain the presence of surface defects. Subsequently the photocatalytic degradation of crystal violet using the anatase titania nanoparticles under violet light irradiation was studied. Under violet irradiation, the dopant-free anatase titania was able to efficiently photodegrade (at loading of 200 mg/L) 1L crystal violet solution of 20 ppm concentration within 90 minutes. The results indicate that this nano-titania could be used an alternate in the place of the systems reported hitherto in literature, which were either doped with heavy metal-based systems or blended with graphene. The result is a leap forward in sustainable water treatment. © 2025 Elsevier Ltd and Techna Group S.r.l. All rights are reserved, including those for text and data mining, AI training, and similar technologies.