Obtaining TiO₂ Nanostructures By Anodization And Analysis Of Absorbance In The UV-Visible Spectrum For Photocatalytic Application

Vinícius Pereira¹, Luana Soares¹*, Sandra Kunst², Fernando Morisso¹, Roberto Cauduro¹, Cláudia Oliveira¹

¹Universidade FEEVALE; Instituto de Ciências Criativas e Tecnológicas – ICCT/Programa de Pós-Graduação Profissional em Tecnologia de Materiais e Processos Industriais,
Laboratório de Estudos Avançados em Materiais, ERS-239, 2755. Bairro Vila Nova – Novo Hamburgo/RS, CEP 93525-075, (BRAZIL)
²Projeto de Fixação de Recursos Humanos do CNPq – Nível A (RHAE), (BRAZIL)

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ABSTRACT – DOI: https://dx.doi.org/10.47204/EMSR.4.2.2023.089-098

Titanium and its alloys have a wide range of use, in multiple fields in the industry and because it is a biocompatible material, it is widely used in prostheses in the health area. As it is a light material and has a higher melting point compared to steel, for example, it is widely used in metal alloys in various applications. Likewise, its titanium oxides have semiconductor characteristics and excellent corrosion resistance. One of the most used processes to obtain these oxides is through anodization. In this work, TiO₂ was synthesized by anodizing in Psidium guajava electrolyte, for application in heterogeneous photocatalysis. The anodizing process occurs through the formation of an oxide layer on the surface of a metal through the transmission of a potential difference submerged in an aqueous solution. In the specific case of this work, this electrochemical method leads to the modification of the titanium surface, where there is the growth of titanium oxide (TiO₂) on the Psidium guajava substrate. Anodized samples were evaluated for morphology by means of Scanning Electron Microscopy (SEM) analysis. Furthermore, the behavior of these oxides was evaluated through electrochemical chloride corrosion tests. The wettability of the oxides was tested by the sessile drop method. For the analysis of the absorbance, tests were carried out in the UV-visible region, in a PerkinElmer Lambda 265 spectrophotometer, which allow the collection of data on the light that is emitted during the absorption of radiant energy. The results obtained indicate that it is possible to anodize titanium in Psidium guajava. The best anodizing conditions showed that the current density should be low, 0.1mA/cm², and at low temperature, 0°C, regardless of the anodizing time. The samples anodized in Psidium guajava electrolyte were more resistant to corrosion when compared to oxides produced in traditional electrolytes. Under these anodizing conditions, the maximum potentials obtained are around 10V, and indicate that these samples can serve as an ecologically correct alternative, encouraging the use of clean technology, preserving the environment and ensuring the safety of the process..