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Novel AgBr/TiO2/(I/S) composite was synthesized by deposition–precipitation method. The AgBr/TiO2/(I/S) composite was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectra, UV–Vis diffuse reflectance spectra and the N2 adsorption/desorption instrument. Under visible light irradiation, AgBr/TiO2/(I/S) composite displayed much higher photocatalytic activity than that of pure I/S in the degradation of Rhodamine B (RhB). The RhB dye was degraded by 89% in less than 100 min. All results indicated that AgBr/TiO2/(I/S) composite have good photocatalytic activity and chemical stability. Moreover, ·O2− is demonstrated to be the dominant radical for the photocatalytic degradation of RhB. [ABSTRACT FROM AUTHOR]

In this study, a series of CuO/CdS composites were synthesized by thermal oxidation and successive ionic layer adsorption and reaction (SILAR). The as-prepared CuO/CdS composites were investigated by x-ray diffraction (XRD), field emission high-resolution scanning electron microscopy (FESEM) and energy-dispersive spectrometry. Their photocatalytic activity was investigated by monitoring the degradation of methylene blue (MB) under ultraviolet and visible light irradiation. The XRD pattern indicated that the precursor was cubic-phase CuO and Cu2O. FESEM results indicate that changes in annealing time and temperature have an effect on morphology, but the nanowire structures are preserved. The growth mechanism of the CuO nanowires is discussed in detail. Furthermore, the photocatalytic degradation rate of the MB, determined using an ultraviolet-visible spectrophotometer (UV-vis, UV-2600, Shimadzu), indicates that CdS can significantly improve the absorption of visible light from the sun. [ABSTRACT FROM AUTHOR]

g-C3N4 with porous structure has been synthesized by a thermal polymerization method and its specific surface area regulated by changing the calcination temperature. The as-prepared g-C3N4 was characterized by x-ray diffraction (XRD) analysis, Fourier-transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray photoelectron spectroscopy (XPS), and ultraviolet–visible (UV–Vis) spectrophotometer. The photocatalytic activity of g-C3N4 was investigated using Methyl Orange (MO) as target pollutant. The results show that the g-C3N4 exhibited a unique porous structure with a specific surface area reaching 142.1 m2/g at 610°C. When the calcination temperature was 570°C, the specific surface area of g-C3N4 was 116.3 m2/g and the photodegradation rate of MO was 65%. Moreover, g-C3N4 retained good photocatalytic stability after being used for five times. The photocatalytic mechanism was also explored by free-radical scavenging experiments. [ABSTRACT FROM AUTHOR]

g-C3N4 is a well-known visible-light-active photocatalyst for the degradation of environmental pollutants. However, its photocatalytic activity is restricted by the small specific surface area and the e−/h+ recombination rate. In order to improve the photocatalytic performance of g-C3N4, AgBr/g-C3N4 composite photocatalyst has been designed. The as-prepared AgBr/g-C3N4 was characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), transmission electron microscope (TEM), Brunauer–Emmett–Teller (BET), X-ray photoelectron spectroscopy (XPS), ultraviolet–visible spectrophotometer (UV–Vis) and room temperature photoluminescence (PL). The photocatalytic activity was evaluated by the photodegradation of methyl orange (MO) under simulated visible-light irradiation. The results show that g-C3N4 is porous structure with a large specific surface area of loading AgBr nanoparticles greatly improves the photocatalytic activity. The AgBr content is optimized to 25 wt%, where the degradation rate of MO can reach 90% after 30 min. The enhancement in photocatalytic performances is mainly attributed to the effective production and transfer of e−/h+ for AgBr can absorb the visible light. Moreover, ·O2− is demonstrated to be the dominant radical for the photocatalytic degradation of MO. [ABSTRACT FROM AUTHOR]

Novel urchin-like ZnO nanostructures were successfully synthesized via an electrodeposition-hydrothermal method and characterized using various analytical instruments. The as prepared samples were characterized by FESEM, XRD, UV-Vis, PL and photocatalytic test. And the effects of the electrodeposition time on the morphology, structure and optical properties have been investigated. In the FESEM, well defined shape of urchin-like ZnO nanostructures was generated. The band gaps of urchin-like ZnO nanostructures, determined from UV-Vis absorption spectra, are 3.13 eV. Photocatalytic investigation of ZnO nanostructures was carried out using methylene blue aqueous solution under UV-visible illumination. Urchin-like ZnO nanostructures prepared under 10 min showed enhanced photocatalytic performance in comparison with the others. The enhanced photocatalytic activity for urchin-like ZnO nanostructures might be resulting from the higher concentration of surface oxygen vacancies. [ABSTRACT FROM AUTHOR]

Urchin-like hierarchical ZnO nanostructures consisting of cone-shaped nanorods have been successfully obtained by electrodeposition-hydrothermal method. The as prepared samples were characterized by FESEM, XRD, UV–vis, PL and photocatalytic test. We have studied the important influence of hydrothermal time on the structural, morphological and optical properties. In the FESEM images, the cone-shaped ZnO nanorods radiate from the center of the nanostructures forming a spherical urchin-like shape with a diameter of 5–10 µm. The average diameter and the length of the cone-shaped ZnO nanorods can be identified as 0.1–1 µm and 3–5 µm, respectively. In the PL spectra, a violet emission band at about 402 nm and two blue emission bands at about 446 nm and 465 nm can be observed at room temperature. In comparison with the others, urchin-like ZnO nanostructures prepared under 4 h showed enhanced photocatalytic performance. The enhanced photocatalytic activity of urchin-like ZnO nanostructures might be resulting from the higher concentration of surface oxygen vacancies. [ABSTRACT FROM AUTHOR]