Search

The presence of bromate in water is a well-known problem because of its toxic effects on human health, particularly its carcinogenic potential. Photocatalytic reduction is an attractive process for bromate removal. F- and Fe-codoped TiO2 (F-Fe-TiO2) with a {001} facet was successfully prepared, and its bromate-removal activity under visible light was examined. The microstructure, morphology, and chemical state of the doping elements and the optical property of the photocatalysts were examined using transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), electron paramagnetic resonance (EPR), photoluminescence spectroscopy (PLS), and UV-Vis diffuse reflectance spectra (DRS). The results indicate that the optical properties of F-Fe-TiO2 with the {001} facet and cuboid morphology were obviously improved and its photocatalytic activity was significantly enhanced. The bromate solution of 100 μg/L was thoroughly removed with 0.5 g/L dosage of 1.0% F- and 0.08% Fe-codoped TiO2 composite within 1 hour under visible light. [ABSTRACT FROM AUTHOR]

Hierarchical flower-like Bi2WO6 was successfully synthesized by facile hydrothermal method at low pH. And Ag/AgCl was loaded by photoreduction on its surface. As-prepared photocatalysts were characterized by various techniques. Bi2WO6 was successfully synthesized at a size of 2-3 μm. Depositing Ag/AgCl did not destroy the crystal structure, and both Ag+ and metallic Ag0 were found. The band gap of the composite was 2.57 eV, which indicates that visible light could be the activating irradiation. In the photocatalytic activity test, the composite with 10 wt% Ag/AgCl boasted the highest removal efficiency (almost 100%) in 45 min. The significant enhancement can be attributed to the surface plasmon resonance (SPR) effect and the establishment of heterostructures between Ag/AgCl and Bi2WO6. A possible mechanism of photocatalytic oxidation in the presence of Ag/AgCl-Bi2WO6 was proposed. This work sheds light on the potential applications of plasmonic metals in photocatalysis to enhance their activities. [ABSTRACT FROM AUTHOR]

A series of new two semiconductor catalysts, Co3O4/CeO2, were prepared by glycine-nitrate combustion method for photocatalytic reduction of carbon dioxide to produce methanol and ethanol under visible light (λ>400 nm) irradiation. The catalysts were characterized by BET, UV-vis spectra, XRD, SEM, PL, and XPS and the results indicated that the catalyst with 5 wt.% of Co3O4 has the highest yield among all kinds of tests with the methanol yield of 1.52 μmol·g−1·h−1 and the ethanol yield of 4.75 μmol·g−1·h−1, which are about 2.34 and 1.71 times as large as those of CeO2. However, methanol and ethanol can hardly be detected for Co3O4 under the same condition because of its too narrow band gap. The improvement of the photoreduction activity of Co3O4 doped CeO2 was caused by the separation of electron-hole pairs of Co3O4/CeO2 and charge transfer between Co3O4 and CeO2, mimicking the Z-scheme in photosynthesis. [ABSTRACT FROM AUTHOR]

The photocatalytic degradation of methyl violet using TiSiW12O40/TiO2 as a novel eco-friendly catalyst under simulated natural light irradiation was investigated. The physical characterizations were carried out by TG/DTA, FT-IR, XRD, andUV-visible spectra. The effects of the initial methyl violet concentration, the solution pH, and catalyst dosage on the photocatalytic degradation rate of methyl violet were also examined. The results demonstrated that at optimal condition (initial concentration of methyl violet is 20mg/L, catalyst dosage is 0.3 g, and the pH is 5.5), the degradation rate of methyl violet is as high as 82.4% after 3 h under simulated natural light irradiation. The reaction of photocatalysis for methyl violet can be expressed as first-order kinetic model. [ABSTRACT FROM AUTHOR]