Adsorption of tetrabutylammonium cations on negatively charged surfaces ofthe Hg, Ga, In-Ga, and TI-Ga electrodes

Differential-capacitance curves are measured in aqueous solutions of 0.05 M Na2SO4 + [(C4H9)(4)N]BF4 on electrodes of mercury, gallium, and In-Ga and TI-Ga alloys. By the regressive analysis of the domains in nonequilibrium C vs. E curves, which correspond to cathodic adsorption-desorption peaks, th e adsorption parameters of tetrabutylammonium cations are calculated for ea ch electrode within the model of two parallel capacitors supplemented by th e Frumkin isotherm. It is concluded that the different adsorption behavior of cations (C4H9)(4)N+ on the gallium metals at high negative charges of th e electrode correlates with different "electrochemical work functions." It is found that the behavior of the mercury electrode does not fit in this co rrelation.