Avaliação fotocatalítica do TiO2 Funcionalizados com Nanopartículas Metálicas

Abstract

The present study aimed to evaluate the photocatalytic activity of TiO₂ functionalized with metal nanoparticles for the degradation of the Ponceau 4R dye. To this end, TiO₂ was synthesized by the sol-gel method, followed by hydrothermal treatment to enhance its properties. The incorporation of metal nanoparticles was performed by photodeposition. The materials were characterized by thermal analysis, Fourier transform infrared pectroscopy, and X-ray diffraction. X-ray diffraction (XRD) analysis confirmed that the anatase phase crystal structure of TiO₂ was maintained in all samples, and thermal analysis indicated that the material is thermally stable up to 600 °C. The experimental photodegradation results of the Ponceau 4R dye demonstrated that silver-functionalized TiO₂ performed better, achieving a decolorization efficiency of 83% in 120 minutes, superior to both pure TiO₂ (64%) and copper-modified TiO₂ (54%). Silver's high efficiency is explained by its ability to capture electrons, preventing the recombination of electron-hole pairs and, consequently, increasing the production of oxidizing free radicals. Conversely, exchange with copper proved inefficient, inhibiting photocatalytic activity by acting as a recombination center for electrons and holes.