Spatio-temporal interfacial potential patterns during the electrocatalyzedoxidation of formic acid on Bi-modified Pt

Citation
J. Lee et al., Spatio-temporal interfacial potential patterns during the electrocatalyzedoxidation of formic acid on Bi-modified Pt, J CHEM PHYS, 115(3), 2001, pp. 1485-1492
Citations number
46
Categorie Soggetti
Physical Chemistry/Chemical Physics
Journal title
JOURNAL OF CHEMICAL PHYSICS
ISSN journal
00219606 → ACNP
Volume
115
Issue
3
Year of publication
2001
Pages
1485 - 1492
Database
ISI
SICI code
0021-9606(20010715)115:3<1485:SIPPDT>2.0.ZU;2-#
Abstract
We report experimental observations of the spatio-temporal dynamics in the electro-oxidation of formic acid on a Pt ring electrode modified by bismuth adatoms. Bismuth modification significantly enhanced the current density a nd it was found to considerably increase the existence range of oscillation s and spatio-temporal self-organization. Hidden negative differential resis tance and the existence of a Hopf bifurcation were deduced from the electro chemical impedance spectra and the occurrence of galvanostatic oscillations . The pattern formation resulted from hybrid effects of the nonlinear chemi stry during formic acid oxidation and the long-range coupling of the interf acial potential induced by the chosen geometry (ring type) of the working e lectrode. Reversible transitions between traveling pulses and oscillating s tanding waves were observed when the outer potential or the formic acid con centration near the electrode were used as control parameters. Experimental results were compared with computer simulations of a reaction-migration sy stem. The role of electrode inhomogeneities in pattern formation and the tr ansform between patterns were discussed. (C) 2001 American Institute of Phy sics.