Influence of Citric Acid/Metallic Cations Ratio in the Structure,Morphology and Photocatalytic Activity of TiO_2 Prepared by Pechini Method

摘要

Abstract. This aim of this work is to evaluate the influence of citric acid/metallic cation ratio of 3:1, 4:1 and 5:1 used in the TiO_2 synthesis by Pechini method in the structure, morphology and photocatalytic activity of methyl red dye. The prepared samples were characterized by X-ray Diffraction (XRD) using Rietveld refinement method, textural analyses, and photocatalytic activity. The results obtained by XRD technique confirm the efficiency of the Pechini method in the preparation of TiO_2 samples with nanosize particle. All samples present anatase phase and presence of rutile as secondary phase with content of 15.6, 10.5 and 18.3%. The isothermal adsorption showed that samples have mesopores characteristics and morphology with irregular shape agglomerates. The sample 4:1 presented better photocatalytic performance discoloring 70% of dye in 24h, indicating that the presence of 10.5% of rutile phase jointly with anatase phase improve the photocatalytic activity.