Enhanced visible light absorption of shape-controlled TiO2@Fe2O3 composites
Milena Synowiec, Karolina Zazakowny
Quarterly No. 3-4, 2020 pages 157-162
DOI:
keywords: titanium dioxide nanocrystals, narrow band gap semiconductor, hematite, visible light absorption, TiO2@Fe2O3 composites
abstract This article presents titanium(IV) oxide nanocrystals in the crystalline form of anatase obtained by hydrothermal synthesis using various shape-controlling agents. Two methods were applied. In the first, diethanolamine (DEA) was used as the shape-controlling agent and titanium(IV) isopropoxide (TTIP) as the TiO2 precursor. In the second method, carbonate ions were responsible for controlling the shape, while potassium titanate nanowires (KTNWs) were the precursor of TiO2. The expected application of the nanocrystals was related to the absorption of visible light. Therefore, the main goal was to modify shape-controlled TiO2 with a narrow band semiconductor providing absorption of light in that range. Based on spectrophotometric analysis, it was found that the TiO2@Fe2O3 composites possess a band gap in the range between 2.21 and 2.30 eV which originates from the Fe2O3 nanoparticles. Moreover, a small amount of Fe3+ ions was incorporated into the TiO2 lattice, as evidenced by the band gap ranging from 2.85 to 2.95 eV.