Investigation of TiO2 Deposit on SiO2 Films: Synthesis, Characterization, and Efficiency for the Photocatalytic Discoloration of Methylene Blue in Aqueous Solution

TiO2-SiO2 thin films were created on Corning glass substrates using a simple method. Nine layers of SiO2 were deposited; later, several layers of TiO2 were deposited, and their influence was studied. Raman spectroscopy, high resolution transmission electron spectroscopy (HRTEM), an X-ray diffractometer (XRD), ultraviolet-visible spectroscopy (UV-Vis), a scanning electron microscope (SEM), and atomic force microscopy (AFM) were used to describe the sample's shape, size, composition, and optical characteristics. Photocatalysis was realized through an experiment involving the deterioration of methylene blue (MB) solution exposed to UV-Vis radiation. With the increase of TiO2 layers, the photocatalytic activity (PA) of the thin films showed an increasing trend, and the maximum degradation efficiency of MB by TiO2-SiO2 was 98%, which was significantly higher than that obtained by SiO2 thin films. It was found that an anatase structure was formed at a calcination temperature of 550 degrees C; phases of brookite or rutile were not observed. Each nanoparticle's size was 13-18 nm. Due to photo-excitation occurring in both the SiO2 and the TiO2, deep UV light (lambda = 232 nm) had to be used as a light source to increase photocatalytic activity.

Automated summary

TiO2-SiO2 thin films were created on Corning glass substrates using a simple method. The photocatalytic activity of the films increased with the increase of TiO2 layers, reaching a maximum degradation efficiency of 98% for methylene blue. The films exhibited an anatase structure and the size of each nanoparticle was 13-18 nm. Deep UV light was necessary to increase the photocatalytic activity due to photo-excitation in both SiO2 and TiO2.