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Potential Oscillations and S-Shaped Polarization Curve in the Continuous Electro-Oxidation of CO on Platinum Single-Crystal Electrodes.

DE2005836369

Publication Date	2005
Personal Author	Koper, M. T. M.; Schmidt, T. J.; Markovic, N. M.; Ross, P. N.
Page Count	20
Abstract	The occurrence of an S-shaped polarization curve in a simple model for the continuous electrochemical oxidation of CO on a platinum electrode is discussed. In the model, the S-shaped polarization curve is caused by the competitive Langmuir-Hinshelwood mechanism between surface-bonded CO and OH. The reaction is studied experimentally on single-crystal platinum rotating disk electrodes in perchloric and sulfuric acid solution, and it is shown that the voltammetry is in good agreement with the model predictions. When studied under current-controlled conditions, a fast galvanodynamic scan indeed suggests the existence of the S-shaped polarization curve. At lower scan rates, however, irregularities and small-amplitude irregular fluctuations or oscillations in potential are observed. Very regular potential oscillations under current-controlled conditions are observed only on Pt(111) in sulfuric acid. The possible origin of these irregularities and oscillations is discussed in relation to the existing theories of electrochemical instabilities
Keywords	Polarization Electrodes Electrochemical oxidation Carbon oxide Oxidation Single crystal Perchloric acid Sulfuric acid Vollammetry Carbon oxide (CO) Langmuir-Hinshelwood model
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Technische Univ. Eindhoven (Netherlands). Lab. for Inorganic Chemistry and Catalysis.; Department of Energy, Washington, DC.; Lawrence Berkeley National Lab., CA.
Supplemental Notes	Prepared in cooperation with Lawrence Berkeley National Lab., CA. Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200521

Potential Oscillations and S-Shaped Polarization Curve in the Continuous Electro-Oxidation of CO on Platinum Single-Crystal Electrodes.

Potential Oscillations and S-Shaped Polarization Curve in the Continuous Electro-Oxidation of CO on Platinum Single-Crystal Electrodes.
DE2005836369

Publication Date	2005
Personal Author	Koper, M. T. M.; Schmidt, T. J.; Markovic, N. M.; Ross, P. N.
Page Count	20
Abstract	The occurrence of an S-shaped polarization curve in a simple model for the continuous electrochemical oxidation of CO on a platinum electrode is discussed. In the model, the S-shaped polarization curve is caused by the competitive Langmuir-Hinshelwood mechanism between surface-bonded CO and OH. The reaction is studied experimentally on single-crystal platinum rotating disk electrodes in perchloric and sulfuric acid solution, and it is shown that the voltammetry is in good agreement with the model predictions. When studied under current-controlled conditions, a fast galvanodynamic scan indeed suggests the existence of the S-shaped polarization curve. At lower scan rates, however, irregularities and small-amplitude irregular fluctuations or oscillations in potential are observed. Very regular potential oscillations under current-controlled conditions are observed only on Pt(111) in sulfuric acid. The possible origin of these irregularities and oscillations is discussed in relation to the existing theories of electrochemical instabilities
Keywords	Polarization Electrodes Electrochemical oxidation Carbon oxide Oxidation Single crystal Perchloric acid Sulfuric acid Vollammetry Carbon oxide (CO) Langmuir-Hinshelwood model
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Technische Univ. Eindhoven (Netherlands). Lab. for Inorganic Chemistry and Catalysis.; Department of Energy, Washington, DC.; Lawrence Berkeley National Lab., CA.
Supplemental Notes	Prepared in cooperation with Lawrence Berkeley National Lab., CA. Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200521