Effect of tetrabutylammonium cations on lifting of reconstruction and phase transitions within adsorbed adlayers at Au(100) electrode in halide electrolytes

• TBA increases stability range of Au(100)-(hex) structure in KCl and KBr while in KI does not
• TBA shift spikes of commensurate structure of Br anion adlayers to less positive potentials
• TBA shift spikes of incommensurate structures of Br and Cl anion adlayers in the opposite direction
• TBA shift both spikes in KI to less negative potentials

The influence of tetrabutylammonium (TBA) cations on lifting of reconstruction and phase transitions within adsorbed adlayers at Au(100) electrode in halide electrolytes has been studied by cyclic voltammetry and differential capacity measurements. The presence of TBA cation increases the stability range of the reconstructed surface more in chloride electrolyte than in bromide one in contrast to I− anions which have no impact on stability range. Besides, TBA cations shift the spikes corresponding to the incommensurate structures of Br− and Cl− anion adlayers to less positive potentials and the spike assigned to the commensurate structure of Br− anions in the opposite direction. In iodide electrolyte the two spikes connected most likely with the formation of the ordered cation/anion adlayers occur at less negative potential than the corresponding ones in TBA free solution.