Solution combustion synthesis and visible light-induced photocatalytic activity of mixed amorphous and crystalline MgAl₂O₄ nanopowders

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• 作者：Fa-tang  ; Li^a ;   ; ^{lifatang@126.com} ; Ye  ; Zhao^a ; Ying  ; Liu^a ; Ying-juan  ; Hao^a ; Rui-hong  ; Liu^a ; Di-shun  ; Zhao^b
• 关键词：MgAl₂O₄ ; Spinel ; Amorphous materials ; Solution combustion ; Photocatalytic activity ; Methylene blue
• 刊名：Chemical Engineering Journal
• 出版年：2011
• 出版时间：1 October 2011
• 年：2011
• 卷：173
• 期：3
• 页码：750-759
• 全文大小：1373 K

文摘

Mixed amorphous and crystalline MgAl₂O₄ nanopowders with visible light-induced photocatalytic activity were prepared via a simple solution combustion method using glycine and urea as fuel mixtures. The obtained samples were characterized by X-ray diffraction, field emission scanning electron microscopy, energy-dispersive X-ray, transmission electron microscopy, Brunauer¨CEmmett¨CTeller (BET) surface area, thermogravimetry, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and UV¨CVis diffuse reflection spectrum. The results showed that the combustion was almost complete, the crystallinity and crystallite size of MgAl₂O₄ increased with the increase of fuels, and there was N atoms doped in the catalysts. The MgAl₂O₄ containing amorphism had photo-absorption ability in visible light region. The photocatalytic results for degradation of methylene blue (MB) indicated that the combustion-synthesized samples had photocatalytic activity, whereas the annealed well crystalline MgAl₂O₄ nanopowders had none. The MgAl₂O₄ sample containing about 45.6 % crystalline and 55.4 % amorphous materials showed the highest photocatalytic activity, with a 99.5 % MB removal in 100 min under visible light irradiation. The fluorescence spectra verified that the greater the formation rate of OH radicals, the higher the photocatalytic activity achieved.