Evidence for the existence of a liquid-like layer between a metal electrode and a frozen aqueous electrolyte

The quartz-crystal microbalance (QCM) was used to study premelting at the ice/gold and the frozen electrolyte/gold interfaces. It was shown that in a certain range of temperature, below the melting point, (i) the resonance of the QCM is readily detectable (at temperatures lower than this temperature range the QCM did not show any resonance), (ii) the parameters of the resonance depend on temperature, and (iii) the shape of the resonance is very different from that observed for the QCM in contact with liquids. The observed phenomena were ascribed to the existence of a liquid-like layer (LLL) between ice or frozen, electrolyte and the gold surface. It was shown that for the frozen electrolyte/gold interface the parameters of the QCM resonance depend on potential. The latter, in turn, shows that the properties of the LLL could be controlled by the electrochemical potential of the metal/electrolyte interface.