Synthesis of Porous N-doped TiO2 by Using Peroxo Sol-Gel Method for Photocatalytic Reduction of Cd(II)

Abstract

Porous N-doped TiO2 photocatalyst was successfully synthesized by an environmentally friendly peroxo sol-gel method using polyethylene glycol (PEG) as a templating agent. Here, the effect of PEG addition to the aqueous peroxotitanium solutions on the structure, pore properties and photocatalytic activity of the obtained photocatalysts was systematically studied. The prepared photocatalysts were characterized by X-ray diffraction (XRD), UV-Vis diffuse reflectance spectroscopy (DRS), and Brunauer-Emmett-Teller (BET). It was found that the doping of nitrogen narrows the band gap of TiO2 leading to enhance its visible-light response. The BET analysis shows that the prepared photocatalysts have a typical mesoporous structure with pore sizes of 3–6 nm. The photocatalytic activity of the prepared photocatalysts was evaluated by photocatalytic reduction of Cd(II) in an aqueous solution under visible light irradiation. The results show that porous N-doped TiO2 with the optimal PEG addition had the highest Cd(II) reduction of 85.1% after 2.5 h irradiation in neutral aqueous solution. This significant improvement in photocatalytic activity of the prepared photocatalysts was mainly attributed to the synergistic combination of N doping and porous structure, which could actively increase the catalytic active site of this photocatalysts. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

A New Combination Method of N-doped TiO2 Nanoparticles Synthesis for Heavy Metal Ions Cr(VI) Photoreduction Applications

“…This is different when compared to pure TiO2, which is pure white. This color change was caused by modifying the TiO2 band gap by nitrogen doping, which shifts the optical absorption of this photocatalyst [22]. A detailed explanation of this information will be discussed in the optical properties section supported by UV-Vis spectroscopy analysis.…”

“…It is confirmed that since the undoped TiO2 has a strong absorption on the UV light, it appears in pure white color. In contrast, shifting absorption to the visible region caused all the synthesized N-doped TiO2 to appear yellowish [22]. Figure 3 shows the relationship between the absorption coefficient and the absorbed energy/photon (hv).…”

“…The decrease in the band gap proves that nitrogen has been successfully doped into TiO2 nanoparticles. It is found that nitrogen doping reduced the band gap energy of the synthesized photocatalysts by forming a new N 2p band between the O 2p and Ti 3d valence band in the TiO2 electronic structure [22,26]. Due to the low band gap energy, the synthesized photocatalyst can trigger electron migration from the valence band to the conduction band by absorbing energy from the visible light region [27,28].…”

“…However, TiO2 photocatalyst in the anatase phase has limited application under visible light irradiation due to its inherent high band gap energy (3.2 eV) [22]. In order to overcome this limitation, many efforts have been made to enable its visible light response by doping with transition metals (Ag, Cd, Cu) or non-metallic elements (C, S, N) [23,24,25].…”

Hexagonal Al2O3/TiO2/TiN Nanotubes‐Based Sensor for CO2 Detection

“…[ 12 ] The optical absorbance of TiO 2 in UV and Vis regions limits the generated bandgap (>3.2) that properties decrease the generated electrons in the conducting level and so decreasing its efficiency for gas sensing based on the electric charge attraction. [ 13 ] He et al [ 14 ] used Na 0.23 TiO 2 /TiO 2 and TiO 2 for NOx materials, in which the sensitivity increased very much after doping the TiO 2 with Na atoms.…”