Long-lived nonmetallic silver clusters in aqueous solution: Preparation and photolysis

Journal Article · Wed Jun 06 04:00:00 EDT 1990 · Journal of the American Chemical Society; (USA)

DOI:https://doi.org/10.1021/ja00168a005· OSTI ID:6652056

Linnert, T; Mulvaney, P; Henglein, A; Weller, H ^[1]

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1. Hahn-Meitner-Institut Berlin GmbH (Germany, F.R.)

Radiolytic reduction of Ag{sup +} ions in aqueous solution and reduction by sodium borohydride in the presence of polyphosphate leads to long-lived nonmetallic silver clusters besides particles of metallic silver (having a narrow plasmon absorption band at 380 nm) and quasi-metallic silver (having a blue-shifted and broadened plasmon absorption band). The best conditions for the preparation of cluster solutions are described, and a mechanism of cluster formation is discussed. The Ag{sub 4}{sup 2+} cluster formed in the first stages of Ag{sup +} ion reduction lives for many hours even in the presence of air. It is oxidized by H{sub 2}O{sub 2} and K{sub 2}S{sub 2}O{sub 8}. Its great stability is explained on the basis of the oscillatory behavior of the standard redox potential of silver microelectrodes at very small agglomeration numbers as described previously. Larger clusters with sharp absorption bands at 300, 330, and 345 nm (absorption coefficients of more than 10{sup 4} M{sup {minus}1} cm{sup {minus}1}) are formed in the later stages of Ag{sup +} reduction. They are very sensitive toward air and thermally less stable than Ag{sub 4}{sup 2+}. The absorptions of these clusters are tentatively attributed to CTTS transitions.

• OSTI ID: 6652056
• Journal Information: Journal of the American Chemical Society; (USA), Journal Name: Journal of the American Chemical Society; (USA) Vol. 112:12; ISSN 0002-7863; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400600* -- Radiation Chemistry
AQUEOUS SOLUTIONS
CHARGED PARTICLES
CHEMICAL RADIATION EFFECTS
CHEMICAL REACTIONS
CHEMISTRY
DATA
DATA ANALYSIS
DECOMPOSITION
DISPERSIONS
ELECTROMAGNETIC RADIATION
EXPERIMENTAL DATA
GAMMA RADIATION
INFORMATION
IONIZING RADIATIONS
IONS
MEASURING INSTRUMENTS
MEASURING METHODS
MIXTURES
NUMERICAL DATA
RADIATION CHEMISTRY
RADIATION EFFECTS
RADIATIONS
RADIOLYSIS
SILVER IONS
SOLUTIONS