KOSEN 한인과학기술자네트워크

Nature of color centers in reduced titanium dioxide Kuznetsov VN, Krutitskaya TK KINETICS AND CATALYSIS 37 (3): 446-449 MAY-JUN 1996 Document type: Article Language: English Cited References: 19 Times Cited: 2 Abstract: The nature of color centers in reduced TiO2 was studied by optical diffuse-reflectance spectroscopy in the 3.5-0.5 eV range, thermal-desorption (TD) mass analysis, and temperature-programmed annealing (TPA). The absorption in the 3.0-0.5 eV range with a maximum at similar to 1.24 eV observed in an H-2 or CO atmosphere at T>700 K disappeared in the presence of O-2 at 300 K and P > 10(-3) Pa, and the band at 2.8 eV remained in the spectrum. If no O-2 was admitted, this band was stable upon heating the sample to 600 K. After exposure to O-2, color centers were annealed at 300-550 K. The profile of temperature-programmed annealing (d Delta rho(lambda)/dT) and TD spectra of chemisorbed oxygen were in close agreement and had a common maximum at 400 K. The analysis of the decay mechanism of the O-2 form (with a peak at 400 K in the TD spectrum) allowed one to assign the band at 2.8 eV to oxygen vacancies in the surface and/or to subsurface oxide layers. KeyWords Plus: PHOTOCATALYTIC ACTIVITY, VISIBLE-LIGHT, TIO2, SURFACE, O2, CO Addresses: Kuznetsov VN, ST PETERSBURG STATE UNIV,INST PHYS,ST PETERSBURG 199164,RUSSIA Publisher: MAIK NAUKA/INTERPERIODICA, NEW YORK IDS Number: UW992 ISSN: 0023-1584

please let me know if you want to get any of these two papers! Defect sites on TiO2(110). Detection by O-2 photodesorption Rusu CN, Yates JT LANGMUIR 13 (16): 4311-4316 AUG 6 1997 Document type: Article Language: English Cited References: 47 Times Cited: 21 Abstract: The TiO2(110) surface, prepared with different densities of anion vacancy defect sites, has been investigated by studies of O-2 photodesorption at 105 K. Two separate O-2 photodesorption processes, alpha(1) and alpha(2), are detected and are postulated to be due to the presence of two different types of defect sites produced by annealing the crystal in vacuum before Oz adsorption. The measured photodesorption cross sections for these two states are Q(alpha 1-O2) = (3.1 +/- 0.2) x 10(-16) cm(2) and Q(alpha 2-O2) = (4.3 +/- 0.3) x 10(-17) cm(2) for 3.96 +/- 0.07 eV photons. Both O-2 states photooxidize CO chemisorbed on the reduced TiO2(110) surface. While the yield of the CO2 photoproduct increases with increasing crystal annealing temperature (and increasing defect coverage), the yield of alpha(1)-O-2 and alpha(2)-O-2 passes through a maximum at an annealing temperature of similar to 600 K. KeyWords Plus: SCANNING-TUNNELING-MICROSCOPY, TIO2 SURFACES, INTRINSIC DEFECTS, CO CHEMISORPTION, OXYGEN, PHOTOCATALYSIS, HYDROGEN, SPECTROSCOPY, DESORPTION, ADSORPTION Addresses: UNIV PITTSBURGH,CTR SURFACE SCI,DEPT CHEM,PITTSBURGH,PA 15260 Publisher: AMER CHEMICAL SOC, WASHINGTON IDS Number: XP793 ISSN: 0743-7463 Theoretical study of the interaction of molecular oxygen with a reduced TiO2 surface de Lara-Castells MP, Krause JL CHEMICAL PHYSICS LETTERS 354 (5-6): 483-490 MAR 18 2002 Document type: Article Language: English Cited References: 34 Times Cited: 0 Abstract: We investigate the re-oxidation of the reduced TiO2 (110) surface by adsorption of molecular oxygen using quantum-chemical, ab-initio periodic Hartree-Fock calculations. The absorption sites considered are anion defects and cation Ti(5f) positions. The results show evidence of strong charge transfer from the defect surface to the O-2 molecule. In agreement with experiment, we find that the most stable species is one in which molecular oxygen adsorbs at the defect sites as O-2(-). Adsorption of three O-2 molecules per vacancy site is thermodynamically favored compared to one or two adsorbed molecules. (C) 2002 Elsevier Science B.V. All rights reserved. KeyWords Plus: TIO2(110) SURFACE, HARTREE-FOCK, RUTILE TIO2, ADSORPTION, PHOTOCATALYSIS, PHOTODESORPTION, DIFFRACTION, PRINCIPLES, STATES, WATER Addresses: Krause JL, Univ Florida, Quantum Theory Project, POB 118433, Gainesville, FL 32611 USA Univ Florida, Quantum Theory Project, Gainesville, FL 32611 USA Publisher: ELSEVIER SCIENCE BV, AMSTERDAM IDS Number: 535ZN ISSN: 0009-2614

CPL paper

Finally I was able to download it!! yeah~~~ Langmuir paper Sorry we don't have kinetics and catalysis paper.