ANALYSIS OF SURFACE COVERAGE OF BENZOTRIAZOLE AND 6-TOLYLTRIAZOLE MIXTURES ON COPPER ELECTRODES FROM SURFACE-ENHANCED RAMAN-SPECTRA

The least-squares method has been used to analyze surface-enhanced Ram an spectra of benzotriazole (BTA) and 6-tolyltriazole (B-TTA) mixtures on Cu electrodes. The fractional coverage of these molecules on Cu su rfaces is dependent on their absolute solution concentration, and is c onsistent with an assumed Langmuir adsorption isotherm model. The adso rption equilibrium constant of 6-TTA is found to be about three times that of BTA. This indicates that 6-TTA is more strongly adsorbed on Cu than BTA. The free energy of adsorption for 6-TTA on Cu is 610 cal/mo l lower than that for BTA. (C) 1998 Elsevier Science B.V. All rights r eserved.