Influência dos Parâmetros de Anodização no Crescimento de Nanotubos de TiO2 Visando Sua Aplicação na Fotodegradação de Contaminantes Orgânicos

Abstract

Titanium dioxide (TiO2) is a semiconductor with a prominent position for various applications, mainly due to its chemical stability, non-toxicity, biocompatibility, and environmental friendliness. Among these applications, photocatalytic processes for the degradation of organic compounds and energy storage through the production of green hydrogen stand out. However, despite its promise, many research groups are still seeking to optimize its properties in order to enhance the photocatalytic properties of TiO2 and make its production method simple, inexpensive, and environmentally viable. In this sense, scaling up materials from bulk to nanostructures represents a significant increase in the photocatalytic efficiency of TiO2, as it provides more adsorption/reactive sites and transport pathways. Within this context, this work presents a systematic study of the growth mechanisms of titanium nanotubes (TNTs) using the anodic oxidation technique. For this purpose, metallic titanium (Ti) plates were used as anodes and a metallic copper (Cu) plate as cathodes. Ammonium fluoride (NH4F) solution was used as the electrolyte. Voltages of 10V, 20V, and 30V were used, and anodizing times of 30 min, 60 min, and 120 min were applied. During electrocorrosion, the electrolyte was kept under magnetic stirring and at room temperature by a water cooling system. The distance between the electrodes was kept fixed at 0.5 cm in all electrocorrosions. Once the process was finished, the samples were subjected to heat treatment in a tubular furnace for 2 hours at 450ºC, with a ramp of 5ºC/min, at ambient pressure. The properties of the non-woven fabrics (NTF) were studied by X-ray diffraction, Raman scattering, and Scanning Electron Microscopy. Finally, the photocatalytic properties of the TNTs were evaluated by photodegradation tests of methylene blue dye using a UV light source, which showed greater effectiveness in samples anodized for 60 min at 30 V.