Synthesis of polyaniline-modified Fe3O4 /SiO2 /TiO2 composite microspheres and their photocatalytic application

School of Materials Science and Engineering, University of Science and Technology Beijing, Beijing 100083, PR China
Materials Letters (Impact Factor: 2.27). 06/2011; 65(19-20):2887-2890. DOI: 10.1016/j.matlet.2011.06.005

ABSTRACT Polyaniline-modified Fe3O4 /SiO2 /TiO2 composite microspheres have been successfully synthesized by sol–gel reactions on Fe3O4 microspheres followed by the chemical oxidative polymerization of aniline. The synthesized multilayer-structured composites were characterized by TEM, XRD, TGA, UV–vis diffuse reflectance spectra and magnetometer. The photocatalytic activity was evaluated by the photodegradation of methylene blue under visible light. The effect of polyaniline (PANI) amounts on the photocatalytic activity was investigated. The photocatalytic activity results show that the Fe3O4/SiO2/TiO2 composites with about 2.4 wt.%–4.1 wt.% PANI could show higher photocatalytic efficiency than that of Fe3O4/SiO2/TiO2 . Furthermore, the PANI-Fe3O4/SiO2/TiO2 photocatalyst could be easily recovered using a magnet.

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    ABSTRACT: Magnetically recoverable Fe3O4/BiOCl nanocomposite photocatalysts were fabricated by a simple chemical coprecipitation method at room temperature. The amount of Fe3O4 incorporated into BiOCl was varied from 0 to 20 wt%. The as-synthesized samples were characterized by X-ray diffraction, transmission electron microscopy, energy dispersive spectroscopy, UV–Vis diffuse reflectance spectroscopy, and vibrating sample magnetometer. The obtained results show that the as-synthesized samples mainly contain both crystalline phases (Fe3O4 and BiOCl) and are composed of flower-like nanostructures. Compared to UV light-responsive BiOCl, all the nanocomposite photocatalysts show a strong light absorbance in the range of 250–800 nm, demonstrating that the Fe3O4/BiOCl nanocomposites can respond to visible as well as UV light. Moreover, visible light absorbance was increased with the increase in the Fe3O4 amount in the composite. The photocatalytic activity of nanocomposite photocatalysts was evaluated by the photodegradation of Rhodamine B (RhB) over the samples under visible light irradiation. The 10 wt% Fe3O4/BiOCl nanocomposite photocatalyst shows the highest photocatalytic efficiency among the samples. The Fe3O4/BiOCl nanocomposite photocatalyst was stable under visible light irradiation to efficiently degrade RhB molecules after five cycles and could be easily recovered with a magnet after each cycle.
    Journal of Cluster Science 12/2013; · 1.36 Impact Factor
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    ABSTRACT: In the present study, Fe3O4@SiO2 core–shell microspheres were prepared via two steps. First, Fe3O4 nanoparticles were synthesized by co-precipitation of Fe+3 and Fe+2 as reaction substrates and NaOH as precipitant. Second, the surface of Fe3O4 was coated with silica by hydrolysis of tetraethylorthosilicate as the silica source. Subsequently, in order to reduce the amount of interaction and the agglomeration of Fe3O4@SiO2 microspheres, the silica shell of these particles was modified by vinyltriethoxysilane as the silane coupling agent. The structural properties of the samples were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and Fourier transform infrared spectroscopy analyses. The results indicated that the average sizes of Fe3O4 and Fe3O4@SiO2 particles were about 50 and 500 nm, respectively. Also, the surface characterization of Fe3O4@SiO2 microspheres showed that the silane coupling agent was covalently coupled with the silica surface.
    International Nano Letters. 01/2013; 3(1).


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May 28, 2014