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Oscillatory behaviour in Galvanostatic Formaldehyde Oxidation on Nanostructured Pt/Glassy Carbon Model Electrodes
- Source :
- ChemPhysChem. 11:1405-1415
- Publication Year :
- 2010
- Publisher :
- Wiley, 2010.
-
Abstract
- The electrocatalytic oxidation of formaldehyde, which results in CO(2) 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(2) 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 oscillation patterns increased with decreasing Pt nanodisk density. Lower oscillation frequencies of the electrode potential and lower CO(2) 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.
- Subjects :
- Formates
Surface Properties
Chemistry
Oscillation
Analytical chemistry
Electrolyte
Carbon Dioxide
Glassy carbon
Electrochemistry
Carbon
Atomic and Molecular Physics, and Optics
Nanostructures
Diffusion
Chemical species
Models, Chemical
Formaldehyde
Electrode
Potentiometry
Glass
Physical and Theoretical Chemistry
Cyclic voltammetry
Electrodes
Oxidation-Reduction
Platinum
Electrode potential
Subjects
Details
- ISSN :
- 14397641 and 14394235
- Volume :
- 11
- Database :
- OpenAIRE
- Journal :
- ChemPhysChem
- Accession number :
- edsair.doi.dedup.....57768193e0dc441dd896db322c4868f8