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Published August 1996 | metadata_only
Journal Article

Surface Structures of 4-Chlorocatechol Adsorbed on Titanium Dioxide


TiO_2 has been extensively studied as a photocatalyst for the complete oxidation of a variety of organic pollutants commonly found in groundwater. In this paper, we investigate the surface structures formed between an organic substrate and TiO_2 in the context of understanding how these specific surface interactions affect photoreactivity. The surface complexes formed by 4-chlorocatechol (CT) sorbed on TiO_2 are investigated as a function of concentration and of pH. Singular-value decomposition of the IR spectra of CT adsorbed on TiO_2 indicates that a single bidentate chemisorbed species is present over the pH range of 2−10. The surface-bound species appears to have 40% covalent and 60% ionic bond character. The pH dependence of the adsorption isotherms is modeled using a generalized electric double-layer approach. The data are consistent with the formation of a bidentate binuclear surface group for solution CT concentrations below 50 μM followed by nonspecific multilayer partitioning at concentrations above 100 μM.

Additional Information

© 1996 American Chemical Society. Received for review November 21, 1995. Revised manuscript received April 10, 1996. Accepted April 12, 1996. We are grateful to ARPA and ONR (NAV 5 HFMN N0001492J1901) for financial support.Drs. Ira Skurnick and Harold Guard provided generous support and encouragement. S.T.M. is supported by a National Defense Science and Engineering Graduate Fellowship. J.M.K. is the recipient of a National Science Foundation Predoctoral Fellowship. D.S.P. is a Summer Undergraduate Research Fellow. Wonyong Choi, Peter Green, and Nicole Peill provided critical analyses and stimulating discussion.

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August 19, 2023
August 19, 2023