Efficient photocatalytic reduction of aqueous Cr(VI) over CaSb2O5(OH)2 nanocrystals under UV light illumination
Efficient photocatalytic reduction of aqueous Cr(VI) over CaSb2O5(OH)2 nanocrystals under UV light illumination
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紫外光照射下 CaSb2O5(OH)2 纳米晶体上高效光催化还原含水 Cr(VI)
DOI：
10.1016/j.apcatb.2012.06.001
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发表时间：
2012-08-21
影响因子：
22.1
通讯作者：
Du, Bin
中科院分区：
文献类型：
--
作者：
Chen, Guodong;Sun, Meng;Du, Bin
以CaCl2和KSb(OH)(6)为原料，分别采用传统水热法和微波辅助水热法合成了CaSb2O5(OH)(2)纳米晶。用X射线衍射仪、透射电子显微镜对样品的结构、比表面积和光学性质进行了表征。N-2吸附-脱附等温线和UV-Vis漫反射光谱。光催化还原铬(VI)的结果表明，CaSb2O5(OH)(2)具有比商品P25(Degussa Co.)结果表明，质子供应在还原反应中起着关键作用。随着悬浮液中质子浓度的增加，铬(VI)的光还原速率有系统地加快。甲酸盐离子对体系中铬(VI)的还原也有显著的加速作用。考虑到这些物种在还原过程中起到空穴清除剂的作用，这一观察结果应该是合理的。随后量子产额的提高与H_2SO_4提供的质子相结合，导致了观察到的速率增强。(C)2012爱思唯尔B.V.保留所有权利。
CaSb2O5(OH)(2) nanocrystals were synthesized via traditional and microwave-assisted hydrothermal methods from aqueous solution of CaCl2 and KSb(OH)(6), respectively. The structures, Brunauer-Emmett-Teller (BET) specific surface areas and optical properties of the as-synthesized samples were characterized by X-ray diffraction, transmission electron microscopy. N-2 sorption-desorption isotherms, and UV-vis diffuse reflectance spectra. The results of photocatalytic reduction of aqueous Cr(VI) revealed that CaSb2O5(OH)(2) possessed a superior activity greatly larger than that of commercial P25 (Degussa Co.). It was shown that proton supply played a crucial role in the reduction reaction. The Cr(VI) photo-reduction rates were systematically accelerated as the proton concentration increased in the aqueous suspensions. Formate ions were also shown to exert a dramatic accelerating influence on Cr(VI) reduction in the system. This observation should be rationalized by considering that these species act as hole scavengers in the reduction process. The consequent improvement in quantum yield combines with the protons provided by H2SO4 result in the observed rate enhancement. (C) 2012 Elsevier B.V. All rights reserved.