Oscillatory behaviour in Galvanostatic Formaldehyde Oxidation on Nanostructured Pt/Glassy Carbon Model Electrodes
Artikel i vetenskaplig tidskrift, 2010

The electrocatalytic oxidation of formaldehyde, which results in CO, and HCOOH formation, was investigated under galvanostatic conditions on nanostructured Pt/glassy carbon (GC) electrodes fabricated by employing colloidal lithography (CL). The measurements were performed on structurally well-defined model electrodes of different Pt surface coverages under different applied currents (current densities) and at constant electrolyte transport in a thin-layer flow cell connected to a differential electrochemical mass spectrometry (DEMS) setup to monitor the dynamic response of the reaction selectivity under these conditions. Periodic oscillations of the electrode potential and the CO, formation rate appear not only for a continuous Pt film, but also for the nanostructured Pt/GC electrodes when a critical current density is exceeded. The critical current density for achieving regular osillation patterns increased with decreasing Pt nanodisk density. Lower oscillation frequencies of the electrode potential and lower CO2 formation rate for nanostructured Pt/GC electrodes compared to continuous Pt film at similar applied current densities suggest that transport processes play an essential role. Moreover, from the simple periodic response of the nanostructured electrodes it follows that all individual Pt disks in the array oscillate in synchrony. This result is discussed in terms of the different modes of spatial coupling present in the system: global coupling, migration coupling and mass transport of the essential chemical species, and the coverage of corresponding adsorbates.

cyclic voltammetry

oxidation

oxidation

formic-acid

surface chemistry

electrocatalytic

potential

oxygen reduction reaction

colloidal lithography

methanol electrooxidation

electrochemistry formaldehyde

theoretical treatment

galvanostatic

oscillations

colloidal lithography

microelectrode arrays

electrochemical mass-spectrometry

Författare

Y.E. Seidel

Universität Ulm

Z. Jusys

Universität Ulm

R. W. Lindstrom

Kungliga Tekniska Högskolan (KTH)

Marie Stenfeldt

Chalmers, Teknisk fysik, Kemisk fysik

Bengt Herbert Kasemo

Chalmers, Teknisk fysik, Kemisk fysik

K. Krischer

Technische Universität München

ChemPhysChem

1439-4235 (ISSN) 1439-7641 (eISSN)

Vol. 11 1405-1415

Ämneskategorier

Fysik

DOI

10.1002/cphc.200901029