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M-doped (M = Ce, Zn, Cu) dendritic-like CdS has been synthesized by a hydrothermal method. As-prepared samples were characterized by x-ray diffraction (XRD) analysis, field-emission scanning electron microscopy (FESEM), energy-dispersive spectroscopy (EDS), and ultraviolet-visible (UV-Vis) spectroscopy. Their photocatalytic activity was evaluated in degradation of methylene blue under simulated visible-light irradiation. XRD results revealed that M:CdS is a hexagonal phase at low doping concentration. XRD and EDS results indicated that Ce, Zn, and Cu were successfully introduced into CdS. FESEM results indicated that CdS retains dendritic-like structure at low doping concentration. UV-Vis spectroscopy results indicated that doping with Ce, Zn or Cu can be used to improve the absorbing capability of dendritic-like CdS for visible light, and the doping content affects the bandgap. Photocatalytic results indicated that doping with Ce, Zn or Cu can improve the photocatalytic efficiency of dendritic-like CdS, with highest degradation rates of 93.2%, 91.2%, and 95.5% for Ce:CdS, Zn:CdS, and Cu:CdS, respectively. The photocatalytic mechanism of M:CdS in degradation of methylene blue is also described. [ABSTRACT FROM AUTHOR]

ZnO/Mn hierarchical structures have been synthesized by a facile one-step solution route at room temperature and their structure, morphology, photoluminescence, and photocatalytic activity fully investigated. Reduced crystallite size and increased microstrain of ZnO were found on incorporation of Mn ions. Room-temperature photoluminescence spectra of the as-synthesized ZnO/Mn hierarchical structures presented violet and blue emission. Meanwhile, ZnO/Mn hierarchical structures exhibited enhanced photocatalytic activity compared with pristine ZnO. Optimal content (5%) of Mn ions in the ZnO matrix will lead to the highest photodegradation efficiency. [ABSTRACT FROM AUTHOR]

The ZnO/ZnS/CuS ternary nanocomposites have been successfully synthesized by a simple and cost-efficient three-step synthetic route, namely homogeneous precipitation, chemical conversion and cation exchange. The structures, morphologies and optical properties of the prepared samples were characterized by powder X-ray diffraction, Field emission scanning electron microscopy and Ultraviolet-visible spectroscopy. The X-ray diffraction result demonstrates that the ternary material is the composite of hexagonal wurtzite ZnO, hexagonal wurtzite ZnS and hexagonal covellite CuS. The FESEM images of the ternary nanocomposites with thickness about 15 nm show they are nonuniform lamellas. Compared with ZnO and ZnO/ZnS, the ternary nanocomposites exhibit enhanced optical absorption property in visible-light region. Moreover, the visible-light photocatalysis of ZnO/ZnS/CuS ternary nanocomposites has remarkably improved and we attribute it to its excellent utilization efficiency of visible-light and gradient energy level structure. [ABSTRACT FROM AUTHOR]

A series of ZnFeO ( x = 0, 1, 2, 3, 4 %) powders via a two-step sol-gel method in open system were successfully fabricated. Influence of Fe doping concentration on the structure, morphology, optical properties and photo catalysis properties were investigated by means of X-ray diffraction, scanning electron microscopy, UV-Vis spectrophotometer and photochemical reaction instrument. The results showed that the ZnO powders were hexagonal wurtzite structures and their crystalline sizes and particle diameters decreased with the increase of Fe doping concentration. An increase of visible light absorption value and a decrease in band gap from 3.219 to 3.167 eV were found with the increase of Fe doping concentration, which enable the sample harvest more photons to excite the electron from the valence. Enhanced visible light induced photocatalytic activity has been found in Fe doped ZnO and the ultraviolet light induced photocatalytic properties of the Fe-doped ZnO have been improved greatly compared with undoped ZnO and commercially available TiO (P25). The photocatalytic activities were not significantly affected by the particle size, and the best Fe doping concentration is 1 %. [ABSTRACT FROM AUTHOR]

Feather-like Cd-doped CuO nanostructures were fabricated by a one-step hydrothermal method. X-ray diffraction pattern (XRD) and field emission scanning electron microscopy (FESEM) demonstrated that Cd 2+ entered the crystal lattice of CuO and substituted Cu 2+ without destroying crystal structures to form feather-like CuO nanostructures. The optical property of Cd-doped CuO was investigated by using UV–vis spectrophotometer. A slight blue-shift of optical band gap was observed because of quantum confinement effect. The doped samples exhibited obviously higher absorbance in UV light region and better photocatalytic activity for the photodegradation of methyl blue than the pure CuO nanosheets. [ABSTRACT FROM AUTHOR]

Abstract: The ZnO/ZnS/CuS ternary nanocomposites (ZOSCTN) were synthesized via a three-step chemical method with ZnO/ZnS binary nanocomposites (ZOSBN) as the intermediate and ZnO nanoparticles (ZON) as the initial product. The structural, morphological and optical properties of ZON, ZOSBN and ZOSCTN were characterized by X-ray diffraction, field emission scanning electron microscopy and Ultraviolet–visible spectroscopy. ZOSBN can maintain the morphology and size of ZON. However, after the introduction of the third component, ZOSCTN become blades-like with the thickness about 20–50nm. Moreover, ZOSCTN has markedly improved visible light photocatalytic performance than ZON and ZOSBN because of the high solar absorption and heterostructures interfaces. [Copyright &y& Elsevier]

Zn-doped SnO 2 hierarchical structures were synthesized by a facile and low-cost hydrothermal route using tin chloride and zinc nitrate as inorganic sources. The Zn-doped SnO 2 hierarchical structures were pompon-like and composed of numerous homogenous nanocones which were radiated from one center. The length and diameter of nanocones were gradually decreased with the increase of doping amount, indicating the morphology of the samples could be well controlled by varying the Zn 2+ concentration. Additionally, the feasible growth process of obtained samples was discussed on the basis of the habits of nucleation and crystal growth. The photocatalytic performances of Zn-doped SnO 2 hierarchical structures were systematically investigated in the degradation of methylene blue (MB), methyl orange (MO), rhodamine B (RhB) and Congo red (CR). Compared with pure SnO 2 , the 4.0 wt% Zn-doped SnO 2 hierarchical structure presented superior photocatalytic ability, which could be mainly attributed to both present oxygen vacancies and doped Zn 2+ centers. At last, the possible photocatalytic mechanism was studied by means of the active species trapping experiments as well as the calculated energy band structures. [ABSTRACT FROM AUTHOR]

Mn-doped CuO nanosheets were prepared through a hydrothermal method to enhance their photocatalytic property. The structural and morphological features were monitored by using X-Ray diffraction (XRD) and field emission scanning electron microscopy (FESEM) with energy dispersive spectroscopy (EDS). UV-vis absorption spectra showed the enhance absorption performance both in UV and visible light region. The band gaps were also calculate and the minimum value was 1.25 eV. The photocatalytic activity was investigated by the degradation of methylene blue (MB), which indicated that the photoactivity of samples depended on the amount of Mn2+ incorporated into the CuO lattice. The improved performance of photocatalysts can be attributed to enhanced light absorption and lower electron-hole recombination. [ABSTRACT FROM AUTHOR]