A Study of the Adsorption of Acetonitrile on a Gold Electrode from Aqueous Solutions Using In situ Vibrational Spectroscopy
CALIFORNIA UNIV DAVIS DEPT OF CHEMISTRY
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The structure of the interphase at the goldaqueous solution interface with absorbed acetonitrile was studied by subtractively normalized FTIR spectroscopy SNIFTIRS. Two types of acetonitrile and water molecules were observed in the interphasal region. The first involved chemisorbed molecules in which important vibrational modes are strongly shifted in frequency with respect to that observed in the bulk of the solution. In the case of acetonitrile, adsorption resulted in a C - N stretching band at 2342 cm-1, and for water, a bending mode at 1688 cm-1. The second type of molecule in the double layer with a band at 2261 cm-1 in the case of acetonitrile, and at 1628 cm-1 in the case of water was assumed to be hydrogen bonded to chemisorbed water molecules, and thus located further away from the geometrical interface. A band due to perchlorate ion at 1107 cm-1 is attributed to anions attracted into the double layer by the positive charge on the electrode. No evidence was obtained for contact adsorption of this anion.
- Organic Chemistry
- Physical Chemistry
- Atomic and Molecular Physics and Spectroscopy