The catalytic effects of copper ions on photo-oxidation in TiO2 suspensions: The role of superoxide radicals

	The catalytic effects of copper ions on photo-oxidation in TiO2 suspensions: The role of superoxide radicals
	Du, Yikui 2; Goldstein, Sara 1,3; Rabani, Joseph 1,3
刊名	journal of photochemistry and photobiology a-chemistry
	2011-12-01
卷号	225 期号:1 页码:1-7
关键词	Photocatalysis Titanium dioxide Copper ions Superoxide radicals Dismutation Methanol Formaldehyde
英文摘要	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.
WOS标题词	science & technology ; physical sciences
类目[WOS]	chemistry, physical
研究领域[WOS]	chemistry
关键词[WOS]	pulse radiolytic investigations ; titanium-dioxide ; photocatalytic degradation ; aqueous-solutions ; peroxy radicals ; formaldehyde formation ; oxidative-degradation ; nonionic surfactants ; photonic efficiency ; rapid measurement
收录类别	SCI
语种	英语
WOS记录号	WOS:000298026300001
公开日期	2015-11-17
内容类型	期刊论文
源URL	[http://159.226.238.44/handle/321008/142562]
专题	大连化学物理研究所_中国科学院大连化学物理研究所
作者单位	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
推荐引用方式 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.