Development of an automated apparatus for spray coating and the influence of calcination temperature on titanium dioxide photocatalytic activity

Abstract

This work presents the development of a low-cost device for automated sol-gel solution deposition, using spray coating technique for the synthesis of TiO2 thin films. The as-obtained films were submitted to different thermal treatment with the purpose of investigating the respective impacts on photocatalytic efficiency. The films were characterized through the use of X-Ray Diffraction (XRD), Scanning electron microscope (SEM), Atomic Force Microscopy (AFM), Fourier-Transform Infrared Spectroscopy (FTIR), and UV-Vis spectroscopy. Later, it was indeed confirmed that the anatase phase predominates in the temperature range considered in this research. Better crystallization and larger crystallite size were obtained with the increase of the temperature, leading to a larger surface roughness, consequently exhibiting a good impact on photocatalytic activities and degradation efficiency. Notably, the films calcined at 600 ∘C exhibited the highest efficiency, achieving near-complete degradation of methylene blue within 4 hours under UV light. This work emphasizes the effectiveness of the developed spray coating device in fabricating high-quality TiO2 films and demonstrates the importance of thermal treatment temperature in improving photocatalytic degradation, contributing to practical applications for sustainable water treatment.