Preparation and characterization of nanostructured modified titanates into a TiO2 nanotube array by electrophoretic deposition

Abstract

TiO2-based compounds are extensively studied due to their semiconducting properties. In addition, TiO2 has other important features, such as commercial availability, water insolubility and low toxicity. These features allow its use in photoelectrocatalytic applications for the treatment of organic pollutants in aqueous environments. However, there are still many gaps in terms of oxidation efficiency of these compounds. The main disadvantage is related to weak absorption on TiO2 in the visible region of the spectrum (only 7% of the solar energy is absorbed), compromising its use in solar plants. In order to improve the efficiency of the TiO2 semiconductor, this project aims at incorporating titanate nanotubes into pores of TiO2 nanotubes via electrophoretic deposition-EPD. The initial procedure will be the synthesis of TiO2 nanotubes by electrochemical anodization and the synthesis of titanate nanotubes by hydrothermal reaction. Subsequently, the titanates will be deposited in the pores of TiO2 nanotubes by EPD. As a result, the expectation is to open channels with high specific surface area for rapid transport of charges. This effect may be translated into a greater photocurrent, which can improve the efficiency of the catalytic materials. The pores also may be modified with conductive polymers impregnated in the matrix. This will allow use of these materials in other applications such as semiconductors and batteries. All materials will be characterized morphologically and electrochemically. The results of this project will be compared to those currently studied in the doctoral program conducted at IQSC/USP - GPEA (Grupo de Processos Eletroquímicos e Ambientais). (AU)