Effect of Anions on the Photocatalytic Activity of Fe(III) Salts Impregnated TiO2

Abstract

This present work focuses on the photocatalytic activity of Fe(III) salt-impregnated TiO2 catalysts for studying the effect of anion on the photocatalytic activity of the salt-impregnated catalysts. The salt-impregnated TiO2 photocatalyst samples prepared using FeCl3, Fe(NO3)3, and Fe2(SO4)3 were characterized by X-ray diffraction (XRD), UV−vis diffuse reflectance spectrophotometry (DRS), Fourier transform infrared absorption spectrophotometry (FT-IR), and surface area measurement by N2 adsorption. Fe(III) ion impregnation of TiO2 with different salts is observed to influence photocatalytic degradation of acetophenone. Fe(III) salt anions were observed to influence the initial rate of degradation. For example, the initial rate of degradation of acetophenone decreases with an increase in percentage of Fe(III) ions in the case of the catalysts prepared using ferric nitrate and ferric chloride salts. However, the initial rate of degradation was observed to increase with ferric sulfate impregnated catalysts. The final percentage degradation of acetophenone was found to increase continuously with an increase in Fe(III) ion concentration, irrespective of the anion. These observations have been discussed in terms of influence of the presence of Fe(III) ions on the recombination of the electron and holes generated during UV irradiation of TiO2. Similarly, the effect of anion has been discussed in terms of radical-scavenging ability of chloride and radical-generating ability of sulfate anions.