Photocatalytic reduction of metals in presence of combustion synthesized nano-TiO2
Photocatalytic reduction of metals in presence of combustion synthesized nano-TiO2
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DOI：
10.1016/j.catcom.2007.07.001
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发表时间：
2008-03-20
影响因子：
3.7
通讯作者：
Madras, Giridhar
中科院分区：
文献类型：
--
作者：
Aarthi, T.;Madras, Giridhar
研究了溶液燃烧法合成的纳米TiO 2对Cu（II）和Cr（VI）的光催化还原作用。将该催化剂的效率与商业二氧化钛Degussa P-25的效率进行比较。在Degussa P-25和CS TiO 2存在下，Cu ~（2+）的还原一级反应速率常数分别为0.003和0.018 min（-1）。还原Cr ~（6+）。在Degussa P-25和CS TiO 2存在下，初始速率常数分别为0.007和0.247 min（-1）。因此，与Degussa P-25 TiO 2相比，CS TiO 2中Cu（II）和Cr（VI）的还原速率更高。研究了溶液燃烧合成的TiO 2和Degussa P-25催化剂对Cu（II）和Cr（VI）的光催化还原反应，考察了pH值和初始浓度对反应的影响。Cu（II）和Cr（VI）的光还原速率随pH的变化与驱动力的变化相关，所述驱动力是金属离子的标准还原电位与导带中的电子的能级之间的差。其他金属离子如Zn（II）、Cd（II）、Pb（II）和Mn（II）在两种催化体系中都不能被还原，这归因于它们被光生电子还原的热力学不可行性。(c)2007 Elsevier B. V.保留所有权利。
The photocatalytic reduction of the metal ions, Cu(II) and Cr(VI), was investigated in presence of solution combustion synthesized (CS) nano-TiO2. The efficiency of this catalyst was compared with that of commercial titania, Degussa P-25. For the reduction of Cu2+, the first-order rate constants were 0.003 and 0.018 min(-1) in presence of Degussa P-25 and CS TiO2, respectively. For the reduction of Cr6+. the initial rate constants were 0.007 and 0.247 min(-1) in presence of Degussa P-25 and CS TiO2, respectively. Thus, the rate of reduction of Cu(II) and Cr(VI) is higher in CS TiO2 compared to Degussa P-25 TiO2. The effect of pH and the effect of initial concentration on the photocatalytic reduction of Cu(II) and Cr(VI) in presence of solution combustion synthesized TiO2) and Degussa P-25 catalyst were investigated. The variation of the photoreduction rate of Cu(II) and Cr(VI) with respect to pH correlates with the variation of the driving force, which is the difference between the standard reduction potential of the metal ion and the energy level of the electrons in the conduction band. The other metal ions like Zn(II), Cd(II), Pb(II) and Mn(II) could not be reduced in both the catalytic systems and this is attributed to the thermodynamic infeasibility of their reduction by photo generated electrons. (c) 2007 Elsevier B.V. All rights reserved.