Effect of pH on the Water/{alpha}-Al{sub 2}O{sub 3} (1{bar 1}02) interface structure studied by sum-frequency vibrational spectroscopy

Journal Article · Mon Aug 01 00:00:00 EDT 2011 · Journal of Physical Chemistry. C

DOI:https://doi.org/10.1021/jp2046596· OSTI ID:1082181

Sung, J.; Zhang, L.; Tian, C.; Shen, Y. R.; Waychunas, G. A.

Sum frequency vibrational spectroscopy (SFVS) was used to study the structure of water/{alpha} - Al{sub 2}O{sub 3} (1{bar 1}02 ) interfaces at different pH values. The OH stretch spectra are dominated by interfacial water contributions at lower frequencies, and by bonded hydroxyls on the Al{sub 2}O{sub 3} surface at higher frequencies. Protonation and deprotonation of various oxide functional groups at the {alpha}-Al{sub 2}O{sub 3} surface as pH varies can be monitored quantitatively by changes of the spectrum, allowing their pK reaction values can be estimated. The point of zero charge of the interface is found to be at pH ~ 6.7.

• Research Organization: Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: Earth Sciences Division
• DOE Contract Number: DE-AC02-05CH11231
• OSTI ID: 1082181
• Report Number(s): LBNL-5398E
• Journal Information: Journal of Physical Chemistry. C, Vol. 115, Issue 28; Related Information: Journal Publication Date: 2011; ISSN 1932-7447
• Country of Publication: United States
• Language: English

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36 MATERIALS SCIENCE