Synthesis of titanium dioxide nanotube derived from ilmenite mineral through post-hydrothermal treatment and its photocatalytic performance

Abstract

Ilmenite (FeTiO3) is a suitable mineral to produce titanium dioxide (TiO2) for photocatalyst applications. Therefore, this research was conducted to synthesize TiO2 material from titanium oxysulfate (TiOSO4) extracted from Indonesia local ilmenite mineral (FeTiO3) and to modify this material into TiO2 nanotubes through a hydrothermal process at 150 °C for 24 hours followed by a post-hydrothermal treatment with temperature variations of 80,100, 120, and 150 °C for 12 hours. The purpose was to investigate the effect of the post-hydrothermal variations on the crystal structure, morphology, and optical properties of the TiO2 nanotubes produced. It was discovered from the scanning electron microscopy (SEM) observations that the TiO2 nanotube was successfully derived from the ilmenite precursor. Moreover, the X-Ray diffraction (XRD) analysis of the nanotube crystal structure showed that post-hydrothermal treatment enhanced the crystallinity of the anatase TiO2 phase even though the sodium titanate phase was observed to exist in the structure. The increase in the post-hydrothermal temperature from 80 to 150 °C was also discovered to have led to: 1) a reduction in the unit cell volume from 136.37 to 132.31 Å3 and a decrease in the lattice constant c from 9.519 to 9.426 Å; 2) an increase in density from 7.783 to 8.081 gr/cm3 as well as in the crystallite size from 19.185 to 25.745 nm; 3) a decrease in the bandgap energy (Eg), from 3.33 to 3.02 eV. These characteristics further indicate the ability of the photocatalytic performance of the nanotubes to enhance the degradation efficiency from 87.69 to 97.11 %. This means the TiO2 nanotubes extracted from local FeTiO3 can provide the expected crystal structure and photocatalytic performance