Quantitative investigations of the adsorption of tert-amyl alcohol at the Au (100) / aqueous solution interface

The energetics of adsorption of tert-amyl alcohol (t-AA) onto a gold (100) single crystal electrode surface have been characterized quantitatively using chronocoulometry. The adsorption parameters were obtained from measurements of the charge density at the electrode surface. The precision of these measurements shows a marked improvement over previous results. Film and surface pressures, relative Gibbs surface excesses, Gibbs energies of adsorption, effective dipole moments and electrosorption valencies were determined as functions of the electrode potential and the surface charge density. The maximum surface excess obtained for this system is equal to 4.4 × 10 −10 mol cm −2 and the Gibbs energy is equal to − 17.4 kJ mol −1 at the potential of maximum adsorption (approximately 0.15 V(SCE)). These values are very close to those obtained for the adsorption of t-AA on the mercury electrode. Similarities and differences between the adsorption of t-AA at gold and mercury electrodes are discussed in detail.