Effects of Thermal Treatment on Porous Cerium Titanate Photocatalyst for Ofloxacin Degradation.

Abstract

Cetyltrimethyl ammonium bromide (CTAB) template was used in a sol-gel route to synthesize porous cerium titanate. The fractions of CeTi₂O6, CeO₂, anatase TiO₂ and rutile TiO₂ phases in the materials vary with calcination temperature ranging from 600 to 1000 °C. FT-Far IR spectra prove the far infrared absorption of Ce-O and Ti-O bonds in the materials. The band gap energies of the crystallized materials are around 3.0 eV and are not noticeably affected by calcination temperature. The BET surface area constantly shrinks from 65.4 m²/g at 600 °C to 2.1 m²/g at 1000 °C. Meanwhile, the total pore volume decreases from 0.2057 cm³/g at 600 °C to 0.0024 cm³/g at 1000 °C. The adsorption capacity of the materials drastically decreases with increasing calcination temperature, which is in close relationship to the change of BET surface area. The porous cerium titanate sample obtained at 800 °C has the maximum photocatalytic activity on both ofloxacin degradation and hydroxyl radical productivity. When calcination temperature increases from 600 °C to 800 °C, photocatalytic degradation efficiency is enhanced from 31.2% to 56.7%.