Microheterogeneous dispersion electrolysis with nanoscale electrode-modified zeolites

• Published in: Journal of electroanalytical chemistry (Lausanne, Switzerland) Switzerland), 1997-12, Vol.439 (1), p.97-105
• Main Authors: Bessel, Carol A, Rolison, Debra R
• Format: Article
• Language: English
• Subjects: Chemistry; Electrochemistry; Exact sciences and technology; General and physical chemistry; Kinetics and mechanism of reactions
• ISSN: 1572-6657; 1873-2569
• DOI: 10.1016/S0022-0728(97)00375-6

This study demonstrates the utility of supported nanoscale Pt or RuO 2 particles as ensembles of ultramicroelectrodes for controlled potential electrolyses, including implications for their use in practical electrosyntheses. 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 ( μ≥0.1 M). For [Fe(CN) 6] 3− solutions (in pH 6.86 phosphate buffer), the time for total reduction 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 electrode-modified zeolite added. The use of Pt–NaY dispersed in solutions of low electrolyte content (650 μM) exploits the nanoelectrode nature of the Pt particles and enables effective electron transfer to be conducted at applied potentials similar to those applied in high ionic strength electrolyte. In the absence of dispersed nanoelectrodes, no electrolysis can be sustained under these conditions of high resistance. Divorcing the electrocatalyst from the reactor electrodes allows inexpensive large area feeder electrodes to be used while the dispersed nanoscale 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 normally associated with industrial applications of electrosynthetic schemes: slow reaction times, difficult electrolyte separations, and high electrode costs.