Preparation and Photocatalytic Properties of CdS/F–TiO2 Composites

Abstract

F–TiO2 was prepared by a simple precipitation method using titanium sulfate as the titanium source, hydrogen fluoride as the fluorine source and ammonia as the precipitant. CdS/F–TiO2 composites were prepared by hydrothermal synthesis of CdS and F–TiO2. The surface morphology, crystal phase composition, ultraviolet absorption band, fluorescence intensity, element composition, valence state, specific surface and pore structure of the samples were characterized by using field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), ultraviolet visible absorption spectrum (UV-Vis-Abs), Molecular fluorescence spectrophotometer (PL) and X-Ray photoelectron spectroscopy (XPS) and Surface area analyzer (BET), respectively. The effects of the dosage of the photocatalyst, pH value, the concentration of methyl orange and the addition of H2O2 on the photocatalytic performance were investigated with methyl orange solution as the target degradation product. The results showed the optimum condition for photodegradation of methyl orange by 1% CdS/F–TiO2 is that the pH value, the solid-liquid ratio, the concentration of methyl orange and the dosage of H2O2 is 2, 2 g/L, 10 mg/L and 3%, respectively. Under the same conditions, the degradation rate of methyl orange by 1% CdS/F–TiO2 was 93.36% when 300 W metal halide lamp was irradiated for 20 minutes, which was significantly higher than that of F–TiO2. CdS has a significant effect on the morphology, crystallinity, grain size and the compound probability of electrons and holes after the F–TiO2 modification. The composite causes a significant red shift at the edge of the F–TiO2 light absorption band. The photocatalytic degradation of methyl orange by 1% CdS/F–TiO2 follows the Langmuir-Hinshelwood first-order kinetic model.

CdS Q-Dot-Impregnated TiO2-B Nanowire-Based Photoanodes for Efficient Photovoltaic Conversion in ‘Q-Dot Co-sensitized DSSC’

“…The CdS composite on the surface of TiO 2 -B NW could also have some influence on the electron states around the Ti atom. As a combination of these two effects, the increased electron cloud density of the Ti atom could result in the red shift of the Ti peak in CdS/TNW composite structure . Furthermore, inclusion of the S atom in the TNW lattice may form an O–Ti–S bond, and/or the Cd atom could replace the Ti atom in the lattice to form the Ti–O–Cd bond.…”

“…As a combination of these two effects, the increased electron cloud density of the Ti atom could result in the red shift of the Ti peak in CdS/TNW composite structure. 87 Furthermore, inclusion of the S atom in the TNW lattice may form an O−Ti−S bond, and/or the Cd atom could replace the Ti atom in the lattice to form the Ti−O−Cd bond. Thereby, a change in the density of electron cloud around O atom may modify the lattice constant of TNW in CdS/TNW composite structure.…”

Ni–Al layered double hydroxide-coupled layered mesoporous titanium dioxide (Ni–Al LDH/LM-TiO2) composites with integrated adsorption-photocatalysis performance

“…This stage involves multiple reaction processes, and only some of the methyl orange eventually degraded into CO 2 . 63…”

“…This stage involves multiple reaction processes, and only some of the methyl orange eventually degraded into CO 2 . 63 In this work, LDHs were coupled with LM-TiO 2 to prepare adsorption-photocatalysis integrated LDHs/LM-TiO 2 composites, which displayed good adsorption and photocatalytic properties. The main reasons for this are as follows: (1) compared with simple TiO 2 , LDHs/LM-TiO 2 has a particular layered mesoporous structure, which increases the specic surface area, and more active sites for the photoreaction are provided on the material surface, which are helpful for the photocatalytic reaction.…”

“…For the treatment of industrial wastewater, the traditionally used technologies are mainly chemical, physicochemical, and biological methods, including electrocatalytic degradation, [1][2][3][4] ultrasonic treatment, 5,6 biological occulation, 7,8 adsorption, 9,10 and photocatalytic degradation. [11][12][13][14][15][16] Photocatalytic degradation, namely, photocatalytic oxidation technology, which uses sunlight and simulated natural light as light sources to act on semiconductor catalysts to produce photogenerated electrons and holes, and reacts with O 2 , H 2 O, and other active substances to generate hydroxyl radicals, superoxide radicals, and other active substances, and eventually decomposes pollutants into harmless inorganic small molecules. The commonly used photocatalysts are mainly semiconductor materials, including TiO 2 , [17][18][19] CdS, 20 and ZnO.…”