Estudo comparativo de rotas de síntese de nanorecobrimentos de TiO2 com propriedades fotoativas

Abstract

The increasing generation of organic pollutants, resulting from industrial and urban development, is one of the main environmental concerns of the 21st century. The inadequate disposal of these contaminants into water bodies demands effective and sustainable technological solutions to minimize their impacts. In this context, functional nanomaterials, such as titanium dioxide (TiO₂), have gained prominence due to their physicochemical properties, especially in pollutant photodegradation processes. TiO₂ has been widely studied for its high stability, strong photocatalytic activity under UV radiation, and excellent cost-effectiveness, being applied in sensors, batteries, pigments, and self-cleaning surfaces. Thus, this work aimed to obtain and characterize TiO₂ thin films with self-cleaning properties, synthesized through sol–gel and hydrothermal routes. Five different synthesis routes were proposed for obtaining crystalline solutions and suspensions containing TiO₂ nanoparticles. The thin films were produced using the dip-coating immersion technique. The prepared samples were characterized by X-ray diffraction, diffuse reflectance, transmittance, atomic force microscopy, transmission electron microscopy, and ellipsometry, in order to obtain relevant data regarding morphology, crystalline structure, optical properties, and photocatalytic performance. The induced superhydrophilicity of the coatings was investigated through wettability tests and contact angle measurements between the film surface and a drop of distilled water. The photocatalytic efficiency of the films was evaluated through the degradation of the organic dye rhodamine B, simulating an environmental contaminant. The results indicated great potential for applying these coatings in environmental remediation and self-cleaning surfaces. The SCMicro 5C film degraded more than 40% of the model dye, while the SM 5C film exhibited considerable wettability after a short period under UV-C irradiation, showing a contact angle of 28° before irradiation and less than 10° after irradiation.