The subject of sol-gel electrochemistry is introduced, starting with a brief account of milestones in its evolution. Then, the types of sol-gel materials that are useful for electrochemistry are presented, followed by a description of recent advances in the various fields of sol-gel electrochemistry. Modified electrodes, solid electrolytes, electrochromic devices, and corrosion protection coatings are described. Emerging fields such as RuO 2 supercapacitors and electrochemical synthesis of sol-gel precursors are also addressed.

A general approach to prepare nanodispersions of noble metals in organically modified silicates is presented with particular emphasis on the synthesis of gold nanodispersion and its characterization. Organically modified sol−gel monomers containing amine functional groups are used to stabilize the metal salts before the reduction step and to cap and prevent coagulation of the metal sol after reduction and through gel formation, drying, and aging. Uniform spherical metal nanodispersions of Au, Pt, and Pd with average diameter of 4−6 nm were obtained. The particle size distribution and the average size of silver nanoparticles prepared by the same method were considerably larger. This was attributed to the lower stability of the silver−amine complex and to the lower affinity of amines to silver surfaces. Stable aqueous colloidal solutions and supported metal nanodispersions in porous films and monoliths can be prepared by this route.

A general methodology to prepare redox active inorganic multilayers consisting of copper hexacyanoferrate layers formed by successive self-assembly and solution epitaxy is described. The layers are separated by a mercaptopropionic acid spacer.

A simple strategy is presented for the construction of an electrochemical interface with a tunable kinetic barrier by self-assembling organically modified silica gel and gold nanoparticles. Self-assembly of an organically modified silica layer is carried out from the hydrolyzed sol of the precursor mercaptopropyltrimethoxysilane. The kinetic barrier of this self-assembled silicate film is modified by gold nanoparticles that are self-assembled into the silicate network. The electrochemistry of ferricyanide redox reaction is used as a marker to probe the interface.

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