TETRAALKYLAMMONIUM CATION CLATHRATE HYDRATES IN INTERFACIAL ELECTROCHEMISTRY

Application of tetraalkylammonium cation clathrate hydrates as electro lytes in interfacial electrochemistry has been presented. All experime nts were performed in a wide temperature range, including liquid and s olid electrolyte. It has been shown that the Au/electrolyte interface exhibits constant phase element behavior, with fractional exponent bei ng between 0.7 and 1. No substantial temperature dependence of this pa rameter was noticed. For systems with fractional exponent close to uni ty, the temperature coefficient of the electric double layer capacitan ce is positive for all studied electrolytes. The electrode reaction of redox active ion added to tetraalkylammonium cation clathrate hydrate s was studied. It has been concluded that at temperatures below the me lting point of electrolyte, the motion of redox active ions is restric ted to intergrain spaces of electrolyte. No substantial change of eith er interfacial parameters or apparent diffusion coefficient of redox a ctive ion is observed at temperatures around the melting point of the studied electrolytes. This may suggest a similar structure of electrol yte near the electrode surface at temperatures below and above its mel ting point. (C) 1998 Elsevier Science B.V.