Adsorption behavior of n-butanol molecules on negatively charged surfaces of electrodes of mercury, gallium, and alloys In-Ga and Tl-Ga

By using the bridge technique at a frequency of 420 Hz and temperature of 3 2 degrees C, differential capacitance curves are measured on the Hg/H2O, Ga /H2O, (In-Ga)/H2O, and (Tl-Ga)/H2O interfaces in 0.05 M Na2SO4 solutions wi th different additions of n-C4H9OH. By the regression analysis of these cur ves, adsorption parameters of n-butanol are estimated for the region of cha rges q where the chemisorption of H2O dipoles is absent. On the basis of th e data obtained, it is found that the difference in the adsorption behavior of organic molecules on the metals studied at q much less than 0 is primar ily caused by the difference in the "electrochemical work function" (accord ing to Trasatti's definition), i.e., by the difference in potentials corres ponding to identical, sufficiently large negative values of q.