Synthesis of Sol–Gel Assisted TiO2 Nanostructures for Photocatalytic Degradation of Methylene Blue

Abstract

It is highly needed for future generations to develop a low-cost photocatalysts for the degradation of colored dyes to save our environment. Herein, we report an efficient and low-cost sol–gel method for the synthesis of titanium dioxide (TiO₂) nanostructures. The structural, compositional, optical, and morphological properties of the as-synthesized samples have been analyzed by various analytical techniques, including X-ray Diffraction, Fourier Transform Infrared Spectroscopy (FTIR), Ultraviolet–Visible Spectroscopy (UV–Vis), Energy-Dispersive X-ray Spectroscopy (EDX), and Scanning Electron Microscope (SEM). X-ray Diffraction analysis identified distinct anatase peaks, with the rutile phase emerging only at 900°C, along with increased crystal size and lattice strain. SEM images showed morphological changes, transitioning to spherical nanobeads at higher calcination temperatures, forming either dispersed or clustered structures. FTIR spectra revealed temperature-dependent changes in surface chemistry, indicating the presence of various functional groups. UV–Vis spectroscopy indicated shifts in λmax values, reflecting changes in electronic structure and crystallinity, particularly a shift to 334 nm at 900°C, signaling a significant transformation in electronic structure. EDX analysis confirmed the presence of TiO₂ with minimal impurities. The photocatalytic activity was evaluated by degrading methylene blue under visible light, revealing how TiO₂ properties can be fine-tuned through parameters such as calcination temperature, time, pH, and concentration ratio. Remarkably, TiO₂ calcined at 900°C with 6% concentration revealed nearly complete Methylene Blue degradation after 180 min, highlighting its superior performance among the tested catalysts. This work will deliver a possible route to the synthesis of efficient and low-cost photocatalysts to develop for environmental remediation.