Microwave-assisted green synthesis of nanoscaled titanium oxide: photocatalyst, antibacterial and antioxidant properties

In the present work, microwave-assisted method is used to synthesize TiO₂ nanoparticles from Wrightia tinctoria leaf extract. The synthesized nanoparticles were characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HR-TEM), DLS, ZE, FT-IR, Raman, PL and ultraviolet (UV)–visible studies. The XRD analysis confirmed that the catalyst is composed of anatase tetragonal TiO₂ phase with crystallite size of 9.93 nm. The HR-TEM results show that the particles are in spherical shape with particle size of ~ 22 nm (TiO₂ nanoparticles). The UV–Vis (Tauc plot) spectrum (2.52 eV) of the prepared TiO₂ nanoparticles suggest that intrinsic band gap absorption of TiO₂ and electron transition is from the valence band to conduction band. Furthermore, photocatalytic degradation of organic dyes (methyl blue and methyl orange) was studied under sunlight irradiation using synthesized nanoparticles. The synthesized nanoparticles results show 99% degradation activity as in the case of methyl orange dye compared to methyl blue dye (97%) at 90 min. TiO₂ nanoparticles synthesized using W. tinctoria leaf extract have been found to exhibit more enhanced photocatalyst degradation of organic dyes as compared to other leaf extracts. In addition, the synthesized TiO₂ nanoparticles were tested at various concentrations and these results revealed potential antibacterial activities. Antioxidant activity carried out using DPPH free radical scavenging assay revealed lower IC₅₀ μg/mL value 53.64 for the synthesized TiO₂ nanoparticles, respectively. The present work further suggests that it is an effort to describe an effective, eco-friendly and simple method of TiO₂ nanoparticles synthesis and to evaluate its potential for various medical and industrial applications.