Preparation and photocatalytic property of mesoporous ZnO/SnO2 composite nanofibers

In this paper, we prepared mesoporous ZnO/SnO2 composite nanofibers via the electrospinning technique using zinc acetate (Zn(OAc)(2)) and stannic chloride pentahydrate (SnCl4 center dot 5H(2)O) as precursors, cellulose acetate (CA) as the fiber template, and N,N-dimethylformamide (DMF)/acetone (1:1, v/v) as the co-solvent. The structure and morphology of composite nanofibers were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (DRS) and nitrogen adsorption-desorption isotherm analysis. TEM images showed that the mesoporous ZnO/SnO2 composite nanofibers were composed of grain-like nanopartides. The nanoparticles size increased with the increasing of the calcination temperature from 500 to 900 degrees C. Moreover, the crystal phases, grain sizes, and band gap energy of the mesoporous ZnO/SnO2 composite nanofibers were influenced by the molar ratio of Zn:Sn and the calcination temperatures. The photocatalytic activity of the mesoporous ZnO/SnO2 composite nanofibers toward the decomposition of Rhodamine B (RhB) was investigated. It was found that the photocatalytic activity of the mesoporous ZnO/SnO2 composite nanofibers was dependant on their surface areas, light utilization efficiency, and the separation of photogenerated electron/hole pairs. The maximum photocatalytic activity was shown for composite nanofibers with the molar ratio of Zn:Sn 2:1 and calcination at 500 degrees C for 5h. more or less Zn:Sn ratios lowered the photocatalytic efficiency. A mechanism of the charge separation and photocatalytic reaction for the mesoporous ZnO/SnO2 composite nanofibers was also presented. (C) 2010 Elsevier B.V. All rights reserved.