Sol-gel synthesis, characterization and photocatalytic activity of mixed oxide ZnO-Fe2O3

Abstract

Synthesis by sol-gel method of mixed semiconductor ZnO-Fe2O3 was carried out using inorganic salts as precursors. The powders were synthesized at different pH (neutral and basic) in order to study its influence on the properties of the catalysts. These materials were characterized by thermal analysis TGA-DTA, X-ray Diffraction, FTIR spectroscopy, scanning electron microscopy and X-ray energy dispersive spectroscopy. The specific surface area of the solids was calculated from nitrogen adsorption isotherms by BET method. The band gap energy (E g ) of the catalysts was obtained from it UV-Vis spectra (diffuse reflectance) when the crystalline phase was formed under thermal treatment at 350°C by 3 h. The incorporation of Fe2O3 to ZnO semiconductor gives as a result a lower E g value for zinc oxide. Catalytic activity of the materials was evaluated using as test reaction the photocatalytic degradation of potassium cyanide in aqueous dissolution. The catalyst ZnO-Fe2O3 synthesized at pH 7 turned out to be superior than sol-gel and commercial ZnO under similar conditions.