Formation of Hematite Nanotubes by Two-Step Electrochemical Anodization for Efficient Degradation of Organic Pollutants

Abstract

[EN] Nowadays, hematite (alpha-Fe2O3) has emerged as a promising photocatalyst for efficient degradation of organic pollutants due to its properties such as suitable band-gap (similar to 2.1 eV), stability against photocorrosion, abundance and low cost. However, some drawbacks such as low carrier mobility and short hole diffusion length limit its efficiency. In order to overcome these issues, self-ordered nanotubes can be synthetized. Anodization is one of the simplest and most economic techniques to produce nanostructures with high control. In the present study, self-ordered hematite nanotubes were synthetized by two-step electrochemical anodization. In two-step anodization, a first-step was actually a pretreatment to form well-ordered nanoporous template in which well-ordered nanotubes are grown by a second-step. The formed nanotubes were characterized by different methods such as Field Emission Scanning Microscopy and Raman spectroscopy to determine their morphology and crystalline structure, respectively. Furthermore, the obtained nanotubes were characterized by means of photocurrent density versus potential measurements (water splitting) to evaluate their efficiency as photocatalyst. Good results were obtained as the achieved photocurrent density was 0.079 mA cm(-2) at 0.58 V (vs. Ag/AgCl), which indicates that the nanotubes synthetized by two-step anodization are suitable photocatalysts for degradation of organic pollutants.