Knowledge Management System Of Institute of Chemistry，CAS
| The catalytic effects of copper ions on photo-oxidation in TiO2 suspensions: The role of superoxide radicals | |
| Du, Yikui2; Goldstein, Sara1,3; Rabani, Joseph1,3 | |
| 2011-12-01 | |
| Source Publication | JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY
 |
| ISSN | 1010-6030 |
| Volume | 225Issue:1Pages:1-7 |
| Abstract | UV photolysis of aerated aqueous suspensions of TiO2 (Degussa P25) containing CH3OH at pH 8.5 produces HCHO. Addition of CuSO4 affects the rate of HCHO formation (R-HCHO) in two opposite ways. Below 2 mu M, R-HCHO increases with increasing [CuSO4] while at higher concentrations it slows down. The enhancement of R-HCHO at very low [CuSO4] is attributed to catalytic dismutation of O-2(center dot-) forming H2O2 and O-2. At higher [CuSO4], R-HCHO decrease is attributed to removal of mobile holes by copper. Square root dependency of HCHO yield on the absorbed light density is observed in the entire [CuSO4] range used. The square root dependency is generally attributed to competition between second-order electron-hole recombination and first-order trapping, although the lifetime of both electrons and holes is too short to enable their accumulation in the same nano-volume. It is shown here that the electron-hole recombination path involves reaction of the mobile holes with adsorbed O-2(center dot-). The experimental results provide indirect evidence that adsorbed O-2(center dot-) radical ions, which are produced via O-2 reaction with the TiO2 electrons, are important for the well known square root dependency. Unlike the mobile and trapped electrons, O-2(center dot-) has a relatively long lifetime and its accumulation in the nano-volume upon successive absorptions of photons is feasible. It is concluded that the reaction between the accumulated O-2(center dot-) and mobile holes is responsible for the square root law. The decrease of K-d, which has been suggested as a standard parameter for the nature of TiO2 by added Cu(II) implies an apparent improvement of the TiO2 quality as a photocatalyst. (C) 2011 Elsevier B.V. All rights reserved. |
| Keyword | Photocatalysis Titanium Dioxide Copper Ions Superoxide Radicals Dismutation Methanol Formaldehyde |
| DOI | 10.1016/j.jphotochem.2011.07.004 |
| Indexed By | SCI |
| Language | 英语 |
| WOS ID | WOS:000298026300001 |
| Publisher | ELSEVIER SCIENCE SA |
| Citation statistics | |
| Document Type | 期刊论文 |
| Identifier | http://ir.iccas.ac.cn/handle/121111/72914 |
| Collection | 中国科学院化学研究所 |
| Corresponding Author | Rabani, Joseph |
| Affiliation | 1.Hebrew Univ Jerusalem, Accelerator Lab, IL-91904 Jerusalem, Israel 2.Chinese Acad Sci, Natl Lab Mol Sci, State Key Lab Mol React Dynam, Inst Chem, Beijing 100190, Peoples R China 3.Hebrew Univ Jerusalem, Inst Chem, IL-91904 Jerusalem, Israel |
| Recommended Citation GB/T 7714 | Du, Yikui,Goldstein, Sara,Rabani, Joseph. The catalytic effects of copper ions on photo-oxidation in TiO2 suspensions: The role of superoxide radicals[J]. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY,2011,225(1):1-7. |
| APA | Du, Yikui,Goldstein, Sara,&Rabani, Joseph.(2011).The catalytic effects of copper ions on photo-oxidation in TiO2 suspensions: The role of superoxide radicals.JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY,225(1),1-7. |
| MLA | Du, Yikui,et al."The catalytic effects of copper ions on photo-oxidation in TiO2 suspensions: The role of superoxide radicals".JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY 225.1(2011):1-7. |
| Files in This Item: | There are no files associated with this item. | |||||
Items in the repository are protected by copyright, with all rights reserved, unless otherwise indicated.
Edit Comment