Kinetics of the Reaction Between Fe(II) and Ag(I) Catalyzed by Silver Nuclei on TiO2 Surfaces.
AEROSPACE CORP EL SEGUNDO CALIF LAB OPERATIONS
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The one-electron reduction of AgI by FeII 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 AgI 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 FeII to adsorbed AgI. 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
- Inorganic Chemistry
- Physical Chemistry