Study of interfacial charge-transfer complex on TiO{sub 2} particles in aqueous suspension by second-harmonic generation
- Columbia Univ., New York, NY (United States). Dept. of Chemistry
Titanium dioxide (TiO{sub 2}) is a wide band-gap semiconductor having two common crystal forms: rutile and anatase. Due to its high physical and chemical stability, it is extensively studied as a photocatalyst for photolysis of water, and for oxidative photomineralization of organic pollutants in wastewater, aimed at harvesting solar energy. The authors report the first direct observation of an interfacial charge-transfer complex using second-harmonic spectroscopy. The second-harmonic spectrum of catechol adsorbed on 0.4 micron-sized TiO{sub 2} (anatase) colloidal particles in aqueous suspension reveals a charge-transfer band centered at 2.72 eV (456 nm). In addition, the adsorption isotherm of catechol on the colloidal TiO{sub 2} suspension was obtained and gave an excellent fit to the Langmuir adsorption model. From this, the authors infer the free energy of the adsorption to be {Delta}G{degree} = {minus}6.8 kcal/mol.
- OSTI ID:
- 345116
- Journal Information:
- Journal of Physical Chemistry B: Materials, Surfaces, Interfaces, amp Biophysical, Vol. 103, Issue 13; Other Information: PBD: 1 Apr 1999
- Country of Publication:
- United States
- Language:
- English
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