Comparative analysis on the photocatalytic activity of titania and silica nanoparticles using dye discoloration and contact angle test

Abstract

This work was done in order to determine the efficiency of TiO₂ and SiO₂ nanoparticles for photocatalytic activity by using contact angle measurements and dye degradation tests. Covering the mechanism of photocatalysis, which means the promotion of a chemical reaction through the aid of light, the focus here is to apply photocatalysis for the elimination of organic pollutants in water, which is now finding more uses in environmental regeneration. Despite TiO₂-and SiO₂-based nanoparticles may be attractive photocatalysts, there are few reports comparing their efficiency. Both samples were prepared using the sol-gel method; their morphological studies were carried out using a scanning electron microscope attached to an energy dispersion X-ray system. The photocatalytic tests were performed using UV light which was used in the degradation of Rhodamine B and Methylene Blue dyes and the reaction kinetics and efficiency of the photocatalytic process were determined with the help of a UV-visible spectrophotometer. Moreover, the determined hysteresis contact angle described the extent of hydrophilicity or hydrophobicity that resulted from nanoparticles affecting the photocatalytic behavior. As for photocatalytic performance, TiO₂ nanoparticles provided more reactive area and a stronger capacity to generate electron holes when exposed to UV light than SiO₂ so that TiO₂ showed higher photocatalytic activity. The surfaces of TiO₂ NSs coated with a thin layer of TiO₂ showed higher hydrophilicity that enhanced the photocatalytic properties. Not only does this work extend the knowledge on the enhanced photocatalytic performance of TiO₂ in environmental applications, but it also offers valuable guidelines for further research on nanoparticle-mediated photocatalytic applications, by focusing on the connection between surface wettability and photocatalytic efficiency that seems to be underemphasized.