Res. Chem. Intermed.
, Vol. 31, No. 9, pp. 845–856 (2005)
Also available online - www.vsppub.com
Reduction and aggregation of silver ions in tert-butanol
A. SARKAR, S. KAPOOR
and T. MUKHERJEE
Radiation Chemistry and Chemical Dynamics Division, Bhabha Atomic Research Centre,
Mumbai 400 085, India
Received 5 January 2004; accepted 21 January 2005
Abstract—Silver ions undergo reduction reactions induced by radiolytically produced products of
tert-butanol, a commonly used solvent and scavenger for hydroxyl radicals. Radiolytic reduction
of silver ions and the subsequent formation of their clusters are compared with the corresponding
processes in aqueous solution. The surface plasmon UV-Vis absorption band of silver nanocrystallites
obtained by bombardment of tert-butanol solutions of silver salts with electron pulses showed an
absorption maximum at 400 nm. Formation of different sizes of silver nanoparticles was found to be
dependent on the dose rate. The nanocrystallites were found to have an average size of 20 nm.
Keywords: Silver nanoparticles; pulse radiolysis; transmission electron microscopy.
Metal nanoparticles of Ag, Au, Cu, etc. have been known for a long time.
The size-dependent characteristics of the nano-aggregates have been a topic of
current research activity [1–4]. The radiolytic technique is an effective method
for generation of metal clusters in solution. Radiolytic reduction of metal ions
leads to formation of initial clusters, which further grows to form larger metallic
clusters. Formation of clusters by radiolytic methods, like γ -radiolysis and pulse-
radiolysis, also depends on the dose rate [1–4]. For reduction reactions without any
stabilizer, the aggregation process is uncontrolled and leads usually to the formation
of large particles of diameter ranging from 50–100 nm, depending on conditions.
Therefore, to stabilize metal nanoparticles, micelles, crown ethers, surfactants,
vesicles, polymers, etc., are used [1–20].
Metal nanoparticles are widely used as catalysts in organic solvents. Therefore, it
is important to know the stability of metal nanoparticles, as well as the mechanism
of their formation in organic solvents. Various alcohols, as well as polyols and
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