Details
| Original language | English |
|---|---|
| Pages (from-to) | 9811-9815 |
| Number of pages | 5 |
| Journal | Physical Chemistry Chemical Physics |
| Volume | 12 |
| Issue number | 33 |
| Publication status | Published - 1 Jul 2010 |
Abstract
The electrochemical promotion of catalytic C2H4 oxidation has been investigated under low pressure conditions (p≈ 10-6-10-4 mbar) with a Pt film on yttrium stabilized zirconia (YSZ) as catalyst. All measurements were conducted with a UHV system with a differentially pumped quadruple mass spectrometer (QMS) for rate measurements and a photoelectron emission microscope (PEEM) for spatially resolved measurements. A pronounced rate hysteresis upon cyclic variation of p(C2H4) was observed under open circuit conditions which is attributed to carbonaceous CHx adlayer inhibiting O2 adsorption and hence poisoning the reaction. Application of a positive potential causes a partial removal of the inhibiting CHx adlayer by spillover oxygen thus triggering a transition from thus poisoned state of the surface to an active state with reduced carbon coverage. The ignition effect and therefore also the electrochemical promotion effect are linked to the presence of a carbon adlayer on the surface. The non-Faradayicity which is observed in this reaction system is explained as an ignition effect.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- General Physics and Astronomy
- Chemistry(all)
- Physical and Theoretical Chemistry
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In: Physical Chemistry Chemical Physics, Vol. 12, No. 33, 01.07.2010, p. 9811-9815.
Research output: Contribution to journal › Article › Research › peer review
}
TY - JOUR
T1 - Origin of non-Faradayicity in electrochemical promotion of catalytic ethylene oxidation
AU - Toghan, Arafat
AU - Rösken, Liz M.
AU - Imbihl, Ronald
PY - 2010/7/1
Y1 - 2010/7/1
N2 - The electrochemical promotion of catalytic C2H4 oxidation has been investigated under low pressure conditions (p≈ 10-6-10-4 mbar) with a Pt film on yttrium stabilized zirconia (YSZ) as catalyst. All measurements were conducted with a UHV system with a differentially pumped quadruple mass spectrometer (QMS) for rate measurements and a photoelectron emission microscope (PEEM) for spatially resolved measurements. A pronounced rate hysteresis upon cyclic variation of p(C2H4) was observed under open circuit conditions which is attributed to carbonaceous CHx adlayer inhibiting O2 adsorption and hence poisoning the reaction. Application of a positive potential causes a partial removal of the inhibiting CHx adlayer by spillover oxygen thus triggering a transition from thus poisoned state of the surface to an active state with reduced carbon coverage. The ignition effect and therefore also the electrochemical promotion effect are linked to the presence of a carbon adlayer on the surface. The non-Faradayicity which is observed in this reaction system is explained as an ignition effect.
AB - The electrochemical promotion of catalytic C2H4 oxidation has been investigated under low pressure conditions (p≈ 10-6-10-4 mbar) with a Pt film on yttrium stabilized zirconia (YSZ) as catalyst. All measurements were conducted with a UHV system with a differentially pumped quadruple mass spectrometer (QMS) for rate measurements and a photoelectron emission microscope (PEEM) for spatially resolved measurements. A pronounced rate hysteresis upon cyclic variation of p(C2H4) was observed under open circuit conditions which is attributed to carbonaceous CHx adlayer inhibiting O2 adsorption and hence poisoning the reaction. Application of a positive potential causes a partial removal of the inhibiting CHx adlayer by spillover oxygen thus triggering a transition from thus poisoned state of the surface to an active state with reduced carbon coverage. The ignition effect and therefore also the electrochemical promotion effect are linked to the presence of a carbon adlayer on the surface. The non-Faradayicity which is observed in this reaction system is explained as an ignition effect.
UR - http://www.scopus.com/inward/record.url?scp=77955893228&partnerID=8YFLogxK
U2 - 10.1039/c002912b
DO - 10.1039/c002912b
M3 - Article
AN - SCOPUS:77955893228
VL - 12
SP - 9811
EP - 9815
JO - Physical Chemistry Chemical Physics
JF - Physical Chemistry Chemical Physics
SN - 1463-9076
IS - 33
ER -