The interaction of liquid and vapor water with nearly defect-free and defective TiO{sub 2}(100) surfaces

Book · Fri Aug 01 04:00:00 EDT 1997

OSTI ID:500987

Wang, L Q; Baer, D R; Engelhard, M H ^[1]; Skiba, P X ^[2]; Shultz, A N ^[3]

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1. Pacific Northwest National Lab., Richland, WA (United States)
2. Austin Peay State Univ., Clarksville, TN (United States)
3. Oregon State Univ., Corvallis, OR (United States)

The interaction of both liquid and vapor water on nearly defect-free and defective TiO{sub 2}(100) surfaces has been investigated using X-ray photoelectron spectroscopy (XPS) and ultraviolet photoemission spectroscopy (UPS). The study has focused on examining electronic or chemical defects as created in vacuum and after exposure to both liquid and vapor water. Defective surfaces were prepared by electron-beam exposure and Ar{sup +} bombardment. For a nearly defect-free (100) 1 x 1 surface, water coverage was {approximately} 0.02 ML (1ML = 2.9 {times} 10{sup 15}/cm{sup 2}) at 10{sup 4} L exposure to low vapor pressure water, {approximately} 0.08 ML at 10{sup 8} L exposure to higher vapor pressure water, and {approximately} 0.12 ML with liquid water exposure, respectively. Defect intensities were greatly reduced after exposing defective surfaces to {approximately} 10{sup 2} L low vapor pressure water. More significantly, electron-beam induced defects were completely removed upon higher-pressure vapor exposure (> 10{sup 4} L) or liquid water exposure, while defects created by Ar{sup +} bombardment were only partially removed. The adsorption behavior and surface defect reactivity for TiO{sub 2}(100) 1 x 1 surfaces were compared with those for TiO{sub 2}(110) surfaces. The adsorption rates for nearly defect-free (100) 1 x 1 and (110) surfaces are comparable. However, the rate of defect healing for a defective (100) surface is much faster than that for a defective (110) surface.

• Sponsoring Organization: USDOE, Washington, DC (United States)
• DOE Contract Number: AC06-76RL01830
• OSTI ID: 500987
• Report Number(s): CONF-960401--; ISBN 1-55899-335-5
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
36 MATERIALS SCIENCE
CRYSTAL DEFECTS
EXPERIMENTAL DATA
HYDROLYSIS
PHOTOCHEMICAL REACTIONS
SURFACE PROPERTIES
TITANIUM OXIDES
WATER
WATER VAPOR