DOI: https://doi.org/10.55373/mjchem.v26i5.185

Keywords: Titanium dioxide (TiO2); Chromium; Cr-doped TiO2; sol–gel; structural property

Abstract

Titanium dioxide (TiO2) is a widely studied material and is commonly used as a photocatalyst due to its strong oxidation capability and resistance to chemical corrosion and photocorrosion. However, its large band gap and quick recombination of photo-generated electron–hole pairs lead to numerous disadvantages that reduce photocatalytic performance. One of the promising strategies to overcome these issues is by doping TiO2 with metal ions. In this study, pure TiO2 and chromium (Cr)-doped TiO2 nanoparticles with various doping concentrations (1, 3, and 5 wt%) were successfully prepared by a sol–gel method. All samples were characterized using field emission scanning electron spectroscopy (FESEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. The surface morphology of pure and Cr-doped TiO2 nanoparticles shows an agglomeration of spherical shape. The XRD analysis showed that a mixed phase of anatase and rutile started to appear at 1 wt% Cr and the phases remained unchanged until 5 wt% compared to pure TiO2 sample, which showed anatase phase only. The crystallite size of anatase TiO2 decreased from 69.55 to 17.38 nm with 1 wt% Cr doping, whereas the crystallite size of rutile in Cr-doped TiO2 increased slightly from 22.22 nm for 1 wt% to 38.08 nm for 3 wt%. The specific surface area (SSA) for the anatase TiO2 sample was 22.01 m2/g and increased to the highest value of 88.05 m2/g with 1 wt% Cr doping, whereas the highest SSA for rutile was 64.44 m2/g in 1 wt% Cr-doped TiO2. The results indicate that Cr plays an important role in the modification of the structural characteristics of TiO2 nanoparticles.