Article

Growth of dumbbell-like ZnO microcrystals under mild conditions and their photoluminescence properties.

National Laboratory of Superhard Materials, Jilin University, Changchun, 130012, P. R. China.
Inorganic Chemistry (impact factor: 4.6). 08/2007; 46(15):6204-10. DOI:10.1021/ic070008a pp.6204-10
Source: PubMed

ABSTRACT Large-scale uniform dumbbell-like ZnO microcrystals were successfully synthesized via a facile solution method under mild conditions. The as-prepared dumbbells, with lengths of 3.5-5.4 microm and diameters of 1.3-1.8 microm, possess a single-crystal hexagonal structure and grow along the [0001] direction. The influence of the reactant concentration on the size and shapes of the ZnO samples had been studied, and the results revealed that the reactant concentration plays a crucial role in determining final morphologies of the samples. Moreover, the evolution process of the dumbbell-like ZnO microcrystals was viewed by field-emission scanning electron microscopy (FE-SEM) characterization, and a possible formation mechanism was proposed. In addition, optical properties of the ZnO samples prepared at different reaction times were also investigated by photoluminescence (PL) spectroscopy. The room-temperature PL spectrum of the dumbbell-like ZnO microcrystals shows a strong UV emission peak. The UV emission is further identified to originate from the radiative free-exciton recombination by the temperature-dependent PL.

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    Article: Preparation and photocatalytic property of a novel dumbbell-shaped ZnO microcrystal photocatalyst.
    Jian-Hui Sun, Shu-Ying Dong, Yong-Kui Wang, Sheng-Peng Sun
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    ABSTRACT: A novel dumbbell-shaped ZnO microcrystal photocatalyst was successfully synthesized by hydrothermal method in the present study. The prepared ZnO photocatalyst was systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TG-DTA), photoluminescence spectrum (PL) and UV-vis absorption spectrum (UV-vis). The characterizations of dumbbell-shaped ZnO were also compared with the commercial ZnO. The results show that the prepared ZnO photocatalyst has a unique dumbbell shape and it belongs to the hexagonal wurtzite family. In addition, the photocatalytic activity of the prepared dumbbell-shaped ZnO microcrystal photocatalyst was evaluated by the degradation of three different kinds of dyes wastewater (Crystal Violet, Methyl Violet and Methylene Blue). After 75 min reaction, the decolourization efficiencies of the three kinds of dyes wastewater achieved 68.0%, 99.0% and 98.5%, the TOC removal efficiencies achieved 43.2%, 59.4% and 70.6%, respectively. Compared to commercial ZnO, 16-22% higher TOC removal efficiency was obtained by the dumbbell-shaped ZnO. The results indicated that the prepared dumbbell-shaped ZnO microcrystal photocatalyst showed good photocatalytic activity and it could be considered as a promising photocatalyst for dyes wastewater treatment.
    Journal of hazardous materials 09/2009; 172(2-3):1520-6. · 4.14 Impact Factor
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.

Keywords

diameters
 
different reaction times
 
dumbbell-like ZnO microcrystals
 
evolution process
 
facile solution method
 
field-emission scanning electron microscopy
 
final morphologies
 
Large-scale uniform dumbbell-like ZnO microcrystals
 
mild conditions
 
optical properties
 
photoluminescence
 
possible formation mechanism
 
reactant concentration
 
room-temperature PL spectrum
 
single-crystal hexagonal structure
 
strong UV emission peak
 
temperature-dependent PL
 
UV emission