Structures and charging of alpha-alumina (0001)/water interfaces studies by sum-frequency vibrational spectroscopy
Sum-frequency vibrational spectroscopy in the OH stretch region was employed to study structures of water/{alpha}-Al{sub 2}O{sub 3} (0001) interfaces at different pH values. Observed spectra indicate that protonation and deprotonation of the alumina surface dominate at low and high pH, respectively, with the interface positively and negatively charged accordingly. The point of zero charge (p.z.c.) appears at pH {approx}6.3, which is close to the values obtained from streaming potential and second harmonic generation studies. It is significantly lower than the p.z.c. of alumina powder. The result can be understood from the pK values of protonation and deprotonation at the water/{alpha}-Al{sub 2}O{sub 3} (0001) interface. The p.z.c. of amorphous alumina was found to be similar to that of powder alumina.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- Earth Sciences Division
- DOE Contract Number:
- DE-AC02-05CH11231
- OSTI ID:
- 951773
- Report Number(s):
- LBNL-1740E; JACSAT; TRN: US200913%%120
- Journal Information:
- Journal of the American Chemical Society, Vol. 130; Related Information: Journal Publication Date: 2008; ISSN 0002-7863
- Country of Publication:
- United States
- Language:
- English
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