Exploring the Light Energy Band Gap Characteristics of Titanium Dioxide Nanoparticles with Sol–Gel Method and Nanoscale Additives

In recent years, a growing body of research has highlighted the potential of doping titanium dioxide (TiO2) photocatalysts with nanomaterials to enhance their photovoltaic efficiency. These studies have shown that the introduction of dopants can lead to significant improvements by inducing a red shift in the absorption edge towards longer wavelengths or by creating localized states within the TiO2 bandgap. TiO2 has long been recognized as a premier photocatalyst due to its unique properties. However, its inherent bandgap limits its ability to absorb light across a broader spectrum effectively. Doping has emerged as a pivotal strategy to address this limitation by reducing the bandgap and thereby enhancing the photocatalytic activity of TiO2. Our research focused explicitly on narrowing the bandgap of TiO2 through the incorporation of dopants such as indium tin oxide (ITO), fullerene (C60), and single-walled carbon nanotubes (SWCNTs). By introducing these dopants, we aimed to modify the electronic and optical properties of TiO2, enabling it to harness a wider range of solar energy and improve its overall performance as a photocatalyst. Using the sol–gel method and annealing at 550–660 °C temperatures, we produced these doped TiO2 particles to maximize their photocatalytic potential. The bandgap alterations were gauged using UV–Vis Spectroscopy pre and post-doping to evaluate TiO2’s aptness for photocatalysis. The sol–gel synthesis employed titanium isopropoxide, 2-propanol anhydrous, and hydrochloric acid to optimize energy bandgaps for efficient photocatalyst energy production. Our findings highlighted that the most pronounced bandgap reduction occurred with an 8 wt% SWCNTs doping in TiO2, post-annealing at 650 °C.