Accession Number : AD0779925

Title :   Kinetics of the Reaction Between Fe(II) and Ag(I) Catalyzed by Silver Nuclei on TiO2 Surfaces.

Descriptive Note : Interim rept.,


Personal Author(s) : Fleischauer,Paul D. ; Shepherd,John R.

Report Date : 25 APR 1974

Pagination or Media Count : 42

Abstract : The one-electron reduction of Ag(I) by Fe(II) in aqueous solution is catalyzed by nuclei of silver metal on TiO2 single-crystal and thin-film surfaces. The reaction results in the selective precipitation of silver on the catalytic nuclei, forming spherically shaped silver particles that eventually grow together into a continuous film. The kinetics of the reaction show that adsorption of Ag(I) on the substrate TiO2 surface is an important step in the mechanism, the adsorption follows a Langmuir isotherm, and the rate-determining step of the reaction is the electron transfer from Fe(II) to adsorbed Ag(I). Results are presented for two types of catalytic nuclei on TiO2: that introduced by photochemical deposition of silver, and that formed by vapor deposition. Significant differences were observed in the kinetics of the reaction on the two types of silver surface. These differences indicate the need for caution in extending kinetics results for 'model' systems to practical applications. (Author)

Descriptors :   *Charge transfer, *Silver, *Iron, *Surface reactions, Ions, Oxidation reduction reactions, Thin films, Catalysis, Adsorption, Reaction kinetics, Single crystals, Surfaces

Subject Categories : Inorganic Chemistry
      Physical Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE