Enhanced Photocatalytic Activity for Degradation of Methyl Orange over Silica-Titania

Abstract EN

Silica-modified titania (SMT) powders with different atomic ratios of silica to titanium (Rx) were successfully synthesized by a simple ultrasonic irradiation technique.

The prepared samples were characterized by X-ray diffraction (XRD), FT-IR spectroscopy, transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and ultraviolet visible spectroscopy.

The specific surface area was measured according to BET theory.

Results indicate that the addition of silica to titania can suppress the crystalline size growth and the transformation of anatase phase to rutile phase of titania, enlarge specific surface area of the titania particles, and result in a blue shift of absorption edge compared to pure titania.

The photocatalytic activity of the SMT samples was evaluated by decolorizing methyl orange aqueous solutions under UV-visible light irradiation.

It was found in our study that this activity was affected by silica content, calcination temperature, H2SO4, and oxidants such as KIO4, (NH4)2S2O8 and H2O2.

The results reveal that the photocatalytic activity of 0.1-SMT catalyst is the best among all samples calcined at 550°C for 1 h and it is 1.56 times higher than that of Degussa P-25 titania, which is a widely used commercial TiO2 made by Germany Degussa company and has been most widely used in industry as photocatalyst, antiultraviolet product, and thermal stabilizer.

The optimal calcination temperature for preparation was 550°C.

The photocatalytic activity of SMT samples is significantly enhanced by H2SO4 solution treatment and oxidants.