Air purification and disinfection by biosynthesized Cu-doped TiO2 nanoparticles with Aloe vera extract

The use of plant extracts for synthesizing nanoparticles has garnered significant attention due to their simplicity, environmental friendliness, and cost-effectiveness. This study synthesized titanium dioxide (titania, TiO₂) nanoparticles using Aloe vera extract. Its doping with copper was also investigated to reduce the electron/hole pair recombination rate and improve the photocatalytic activity of titania. Biosynthesized titania nanoparticles were characterized by X-ray diffraction (XRD), Diffuse reflectance spectroscopy (DRS), transmission electron microscopy (TEM), and field emission scanning electron microscopy (FE-SEM). XRD reported the formation of crystals with sizes of 4–7 nm by the Scherrer method and 5–27 nm by the Williamson-Hall method. FE-SEM and TEM analysis showed the formation of spherical particles. Spectroscopic results showed that the addition of the copper ion reduced the band gap energy from 3.10 eV to 2.89 eV. It was observed that, under light, increasing the dopant concentration from 1 % to 3 % resulted in an increase in the bacterial removal rate from 93 % to 96 % and the particulate matter removal rate from 91 % to 94 %. Therefore, Cu-TiO₂ nanoparticles biosynthesized with Aloe vera extract exhibited increased photocatalytic and antibacterial activity, which can be utilized for air purification.