Y. Shiraishi et N. Toshima, Oxidation of ethylene catalyzed by colloidal dispersions of poly(sodium acrylate)-protected silver nanoclusters, COLL SURF A, 169(1-3), 2000, pp. 59-66
Citations number
35
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
Silver nanoclusters protected by poly(sodium acrylate) (PAA) were prepared
by UV irradiation of an alcohol-water solution of silver perchlorate in the
presence of PAA. Colloidal dispersions of PAA-protected Ag nanoclusters (P
AA-Ag nanoclusters) were very stable at room temperature for months and com
posed of fine particles with an average diameter of 4.2 nm. X-Ray photoelec
tron spectroscopy data have suggested the O-valency of Ag in PAA-Ag nanoclu
sters. Oxidation of ethylene, catalyzed by PAA-Ag nanoclusters, was perform
ed in glycol under 1 atm. of ethylene/oxygen (2/1 v/v). Products were ident
ified as ethylene oxide by analysis with gas chromatography. Ag nanocluster
s thus prepared had higher catalytic activity than a commercial silver cata
lyst. The oxidation rate catalyzed by the PAA-Ag nanoclusters remarkably in
creased with increasing reaction temperature. PAA-protected Ag nanoclusters
had much higher activity than poly(N-vinyl-2-pyrrolidone) -protected ones
at high temperature. Addition of both cesium and rhenium ions eminently inc
reased the catalytic activity of PAA-Ag nanoclusters. (C) 2000 Elsevier Sci
ence B.V. All rights reserved.