Ca. Bessel et Dr. Rolison, MICROHETEROGENEOUS DISPERSION ELECTROLYSIS WITH NANOSCALE ELECTRODE-MODIFIED ZEOLITES, Journal of electroanalytical chemistry [1992], 439(1), 1997, pp. 97-105
This study demonstrates the utility of supported nanoscale Pt or RuO2
particles as ensembles of ultramicroelectrodes for controlled potentia
l electrolyses, including implications for their use in practical elec
trosyntheses. Microheterogeneous dispersions of nanoelectrode-modified
aluminosilicate zeolites (M-Z) increase the effective electrode area
of conventional large surface electrodes in electrolytes of customary
ionic strength (mu greater than or equal to 0.1 M). For [Fe(CN)(6)](3-
) solutions (in pH 6.86 phosphate buffer), the time for total reductio
n of the iron complex using a dilute 2.5 mg/ml suspension density of 1
wt.% Pt-NaY was 67% less than that for the same solution with no elec
trode-modified zeolite added. The use of Pt-NaY dispersed in solutions
of low electrolyte content (650 mu M) exploits the nanoelectrode natu
re of the Pt particles and enables effective electron transfer to be c
onducted at applied potentials similar to those applied in high ionic
strength electrolyte. In the absence of dispersed nanoelectrodes, no e
lectrolysis can be sustained under these conditions of high resistance
. Divorcing the electrocatalyst from the reactor electrodes allows ine
xpensive large area feeder electrodes to be used while the dispersed n
anoscale electrodes can be a small mass of a high cost electrocatalyst
. These studies demonstrate that heterogeneous dispersion electrolyses
using electrode-modified zeolites can overcome the difficulties norma
lly associated with industrial applications of electrosynthetic scheme
s: slow reaction times, difficult electrolyte separations, and high el
ectrode costs. (C) 1997 Elsevier Science S.A.