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Copper doped ZnO hierarchical nanostructures have been synthesized with a facile solution route at room temperature. Structural properties of the as-synthesized nanostructures have been studied X-ray diffraction, field emission scanning electron microscopy with energy dispersive. Meanwhile, light-absorption properties were studied with UV-Vis absorption spectroscopy. Photocatalytic performance of Cu-doped ZnO hierarchical nanostructures were evaluated by the light-driven degradation of methylene blue. The results indicated that Cu doping lead to the augment of average crystallite size of ZnO crystals. Moreover, morphological evolution of ZnO nanostructures was found with the addition of Cu ions. The photocatalytic test showed that there is an optimum Cu doping concentration which results in the enhancement of photocatalytic performance of Cu doped ZnO hierarchical nanostructures, compared with pristine ZnO. A novel and reasonable mechanism was proposed. It is believed that the enhanced photocatalytic performance of Cu doped ZnO hierarchical nanostructures can be attributed to the formation of acceptor level (Cu2+-Cu+) in the midgap of ZnO, which improved the utilization of light and separation efficiency of photogenerated electron hole pairs. [ABSTRACT FROM AUTHOR]

The SnO micro/nanostructure with interesting distribution characteristic was synthesized by electrochemical anodization. The structural, morphological and photocatalytic properties of the SnO micro/nanostructure were investigated. The experimental results showed that the SnO displayed an interesting distribution characteristic of concentric annulus. The SnO near the fracture region was uniform and well-defined octahedron-like pattern. By contrast, the SnO away from the fracture region was self-assembled frond-like pattern. A feasible formation mechanism of this unique SnO micro/nanostructure was deduced as well. Moreover, the film exhibited 82.87% photodegradation rate of methylene blue, which was attributed to the strong light absorption and low recombination rate of photogenerated electros and holes. [ABSTRACT FROM AUTHOR]

Novel self-assembled BiVO 4 samples with red blood cell-like shape and flower-like microsphere were successfully synthesized via a facile solvothermal approach by using Na 2 CO 3 or NH 3 ·H 2 O as the pH controlling agent and citric acid as the chelating agent. The photocatalytic activity was evaluated by the photocatalytic degradation of methylene blue (MB) under visible light irradiation. The results showed that both the citric acid and pH controlling agent had great influences on the morphologies of the samples. Besides, the relationship between the morphology and photocatalytic activity was studied in detail. Benefiting from the unique morphology, the prepared BiVO 4 samples exhibited excellent photocatalytic activities for the degradation of MB dye under visible light irradiation. [ABSTRACT FROM AUTHOR]

Hierarchically structured m -BiVO 4 samples with different morphologies have been synthesized via a template-free solvothermal route by adjusting the pH value of the precursor solution. The effects of pH value on structure, morphology and photocatalytic activity were investigated. The results showed that the pH value played a great influence not only on the formation of the hierarchical structures with different morphologies, but also on the preferential crystal growth of the BiVO 4 oriented along {040} facets. The pinwheel-like sample with the highest relative intensities of the diffraction peaks I 040 / I –121 exhibited the best photocatalytic activity for the photodegradation of MB under visible light irradiation. According to the Ostwald ripening process, a possible oriented aggregation mechanism was proposed. [ABSTRACT FROM AUTHOR]

Hierarchically structured m -BiVO 4 samples oriented along {040} facets were successfully synthesized by a template-free solvothermal route in ethylene glycol and water mixed solvents. The photocatalytic activity was evaluated by the photocatalytic degradation of methylene blue under visible light. The results showed that the volume ratio of ethylene glycol/H 2 O played a great influence on the morphology. What is more, the preferential crystal growth of the BiVO 4 oriented along {040} facets could also be affected by the volume ratio of ethylene glycol/H 2 O. The photocatalytic results demonstrated that the lamellar BiVO 4 sample with the highest relative intensities of the diffraction peaks I 040 / I –121 exhibited the best photocatalytic activity. [ABSTRACT FROM AUTHOR]

Abstract: We have prepared Zn1−x Co x O (x=0%, 1%, 2%, 3% and 4%) microspheres via a two-step sol–gel method without grinding and investigated their composition, morphology and magnetic properties by means of X-ray diffraction, scanning electron microscopy and vibrating sample magnetometer, respectively. The X-ray diffraction result demonstrates that Co has been successfully doped into hexagonal ZnO. The scanning electron microscope images of Zn0.98Co0.02O reveal an average particle size around 200nm, which is larger than that of as-prepared ZnO nanoparticles (60nm). Magnetic properties measurement indicates that room temperature ferromagnetism and diamagnetism were obtained in Co-doped ZnO at the same time. [Copyright &y& Elsevier]