Study of Synergistic Effect of Ce- and S-Codoping on the Enhancement of Visible-Light Photocatalytic Activity of TiO₂

Abstract

Different samples of Ce- and S-codoped TiO2 nanoparticles were prepared through simple sol–gel synthesis method by using cerium nitrate hexahydrate as cerium precursor, thiourea as sulfur, and tetrabutyl titanate (TBOT) as titanium precursor. Characterization of prepared samples were done by various techniques such as, X-ray diffraction (XRD), UV–visible diffuse reflectance spectroscopy, transmission electron microscopy, Fourier transformation infrared spectroscopy, photoluminescence spectroscopy, and X-ray photoelectron spectroscopy. The XRD showed the presence of only anatase TiO2 for the single sulfur-doped and cerium- and sulfur-codoped titania samples. XRD analysis also pointed out the decrease in the crystal size with the increase in Ce concentration in the samples. The BET analysis reported an increase in the surface area and decrease in the pore size with the increase in the Ce concentration. The PLS results of the samples first showed a decrease in the intensity of the spectra sync with the reduction of recombination centers when the Ce was introduced in codoped TiO2 with the maximum decrease for 0.04 Ce/S-codoped titania; with the further increase in the Ce concentration in the samples, the intensity of the spectra gradually increased coinciding with the increase in the recombination centers. The recombination centers exhibit a direct relationship with the photocatalytic activity of the samples, which could be evidenced by the decolorization of 25 mg/L solution of AO-7. The activity of codoped samples was first increased by the incorporation of Ce with the maximum degradation for 0.04 cerium- and sulfur-codoped titania. By the further increase in the Ce amount in the Ce- and S-codoped titania samples the activity was shown to decrease gradually.

Enhanced photocatalytic properties of reusable TiO 2 -loaded natural porous minerals in dye wastewater purification

“…Considering that UV light comprises a small part of the solar spectrum (3-5%); the photocatalytic degradation using TiO 2 might be hindered and, in some cases, unfeasible [7].  Low quantum efficiency: the photocatalytic activity of TiO 2 is usually inhibited by the fast recombination of the photo-generated electron-hole pairs after excitation.…”

Active Site of O2 and Its Improvement Mechanism over Ce-Ti Catalyst for NH3-SCR Reaction

“…That means more oxygen vacancies existed on Ce-Ti-400. From our previous study [22], formation of oxygen vacancies was due to the interaction between doping Ce and Ti. On the one hand, the formation of oxygen vacancies could promote low-temperature SCR activity [29]; on the other hand, oxygen vacancies were the adsorption center of oxygen [30].…”

“…However, CeO2 showed two peaks centered at the tempura range from 200 to 300 °C (Peak I) and from 300 to 400 °C (Peak II). For Ce- [22]. Obviously, cloud density of both Ce and Ti increased.…”

“…461.4eV and 462.3-467.2 eV could be assigned to Ti [22]. Obviously, cloud density of both Ce and Ti increased.…”

Synthesis, Characterization and Excellent Photocatalytic Performance of Iron-Carbon-Codoped Mesoporous Titania Nanocrystallines

“…It has been proposed that both the photocatalytic activity and the efficiency of mixed phase (rutile and anatase) TiO 2 were enhanced due to synergic interactions between the two phases, which leads to spatial charge separation and hindered recombination [24]. The rutile and anatase contents in the as-prepared Fe-C-TiO 2 samples can be estimated using the Spurr equation…”