CeO2-TiO2 Photocatalyst: Ionic Liquid-Mediated Synthesis, Characterization, and Performance for Diisopropanolamine Visible Light Degradation

Abstract

CeO2-TiO2 photocatalyst with Ce:Ti molar ratio of 1:9 was synthesized via co-precipitation method in the presence of 1-ethyl-3-methyl imidazolium octylsulfate, [EMIM][OctSO4] (CeO2-TiO2-IL). The ionic liquid acts as a templating agent for particle growth. The CeO2-TiO2 and TiO2 photocatalysts were also synthesized without any ionic liquid for comparison. Calcination was conducted on the as-synthesized materials at 400 ˚C for 2 h. The photocatalysts were characterized using diffuse reflectance UV-Vis spectroscopy (DR-UV-Vis), field emission scanning electron microscopy (FESEM), X-ray powder diffraction (XRD), and surface area and pore size analyzer (SAP). The presence of CeO2 has changed the optical property of TiO2. It has extended the absorption edge of TiO2 from UV to visible region. The calculated band gap energy decreased from 2.82 eV (TiO2) to 2.30 eV (CeO2-TiO2-IL). The FESEM morphology showed that samples forms aggregates and the surface smoothens when ionic liquid was added. The average crystallite size of TiO2, CeO2-TiO2, and CeO2-TiO2-IL were 20.8 nm, 5.5 nm, and 4 nm. In terms of performance, photodegradation of 1000 ppm of diisopropanolamine (DIPA) was conducted in the presence of hydrogen peroxide (H2O2) and visible light irradiation which was provided by a 500 W halogen lamp. The best performance was displayed by CeO2-TiO2-IL calcined at 400 ˚C. It was able to remove 82.0% DIPA and 54.8% COD after 6 h reaction.

Photocatalytic properties of the CeO2‐xTiO2 and TiO2‐xCeO2 (x = 10, 30, and 50 mol%) heterostructures obtained by a MAH

“…As environmental pollution has increased, interest has grown in semiconductor materials with good photocatalytic properties capable of completely mineralizing pollutants 7‐9 . A semiconductor with photocatalytic activity absorbs radiation, having its electrons excited from the valence layer to the conduction layer, thus forming a hole (h + ) in the valence layer and an electron (e ‐ ) in the conduction layer, and in turn, these photoexcited pairs initiate the water cleaning process through oxidation reactions of the pollutants present 10‐14 . Yang et al 15 showed that the V 2 O 5 @ TiO 2 core‐shell structure has a greater capacity in the degradation of methylene blue (MB) dye than pure TiO 2 , due to the impediment of recombination of charge carriers.…”

“…Furthermore, CeO 2 is widely investigated for its excellent optical and electrical properties, 25 high thermal stability, storage, and oxygen transfer capacity, 2,16 and photocatalytic activity in the presence of dyes under solar radiation 8 . TiO 2 ‐CeO 2 heterostructures have a greater capacity to separate the electron/hole photogenerated pairs due to the interface between them 11,26 . Zeng et al 27 showed that the support of TiO 2 on CeO 2 mesoporous enhances the catalytic activity for the gas‐phase oxidation of benzene.…”

Highly Sensitive Electrocatalytic Determination of Formaldehyde Using a Ni/Ionic Liquid Modified Carbon Nanotube Paste Electrode

“…Ionic liquids are stable salts, composed of an organic cation and an organic or inorganic anion, and preserved in liquid state over a wide temperature range [9][10][11]. In the past few years, ionic liquids have emerged as a frontier and novel area of research because of their excellent chemical and physical properties, such as: good solvating properties, high chemical and thermal stability, non-flammability, low toxicity, almost negligible vapor pressure, high conductivity, and wide electrochemical window [12][13][14].…”