ICCAS OpenIR
EPR investigation of the free radicals generated during the photosensitization of TiO2 colloid by hypocrellin B
Wu, T; Xu, SJ; Shen, JQ; Chen, S; Zhang, MH; Shen, T
2001
Source PublicationFREE RADICAL RESEARCH
ISSN1071-5762
Volume35Issue:2Pages:137-143
AbstractThe cation radical of dye produced from the interfacial electron transfer from a surface chelated dye to the conduction band of the colloidal TiO2 was studied by laser flash photolysis and electron paramagnetic resonance (EPR) techniques. The study employed hypocrellin B (HB), a natural photodynamic pigment with strong absorption over the visible light region, as a sensitizer and titanium dioxide as a colloid semiconductor. HB formed a chelate with this colloid semiconductor and exhibited a red-shifted and strongly enhanced absorption in the visible spectrum. Laser photolysis indicated that the electron excitation in the visible absorption band of the chelate resulted in extremely rapid and efficient electron injection from the excited triplet state of the dye into the conduction band of the semiconductor. A transient absorption of cation radical of HB at 570 run was observed. The appearance of cation radical of HB was characterized by EPR spectrometry: the photoinduced EPR signal was not quenched by oxygen and its intensity decreased in the presence of NaI, a typical hole scavenger. The generation of conduction band electrons in HB-sensitized TiO2 system was also verified by the spin elimination of a stable cyclic nitroxide, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO), and by the reduction of methyl viologen (MV2+) to its radical MV+..
KeywordNatural Pigment Titanium Dioxide Colloid Electron Injection Cation Radical Spin Elimination
Indexed BySCI
Language英语
WOS IDWOS:000170220100006
PublisherHARWOOD ACAD PUBL GMBH
Citation statistics
Cited Times:2[WOS]   [WOS Record]     [Related Records in WOS]
Document Type期刊论文
Identifierhttp://ir.iccas.ac.cn/handle/121111/77476
Collection中国科学院化学研究所
Corresponding AuthorZhang, MH
AffiliationChinese Acad Sci, Inst Chem, Ctr Mol Sci, Beijing 100080, Peoples R China
Recommended Citation
GB/T 7714
Wu, T,Xu, SJ,Shen, JQ,et al. EPR investigation of the free radicals generated during the photosensitization of TiO2 colloid by hypocrellin B[J]. FREE RADICAL RESEARCH,2001,35(2):137-143.
APA Wu, T,Xu, SJ,Shen, JQ,Chen, S,Zhang, MH,&Shen, T.(2001).EPR investigation of the free radicals generated during the photosensitization of TiO2 colloid by hypocrellin B.FREE RADICAL RESEARCH,35(2),137-143.
MLA Wu, T,et al."EPR investigation of the free radicals generated during the photosensitization of TiO2 colloid by hypocrellin B".FREE RADICAL RESEARCH 35.2(2001):137-143.
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