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Isothermal Reductio...
Isothermal Reduction of IrO2 (110) Films by Methane Investigated Using In Situ X-ray Photoelectron Spectroscopy
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- Martin, Rachel (author)
- Univ Florida, Dept Chem Engn, Gainesville, FL 32611 USA.,University of Florida
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- Kim, Minkyu (author)
- Yeungnam Univ, Sch Chem Engn, Gyongsan 38541, South Korea.,Yeungnam University
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- Lee, Christopher J. (author)
- Univ Florida, Dept Chem Engn, Gainesville, FL 32611 USA.,University of Florida
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- Mehar, Vikram (author)
- Univ Florida, Dept Chem Engn, Gainesville, FL 32611 USA.,University of Florida
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- Albertin, Stefano (author)
- Lund University,Lunds universitet,Synkrotronljusfysik,Fysiska institutionen,Institutioner vid LTH,Lunds Tekniska Högskola,Synchrotron Radiation Research,Department of Physics,Departments at LTH,Faculty of Engineering, LTH
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- Hejral, Uta (author)
- Lund University,Lunds universitet,Synkrotronljusfysik,Fysiska institutionen,Institutioner vid LTH,Lunds Tekniska Högskola,Synchrotron Radiation Research,Department of Physics,Departments at LTH,Faculty of Engineering, LTH
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- Merte, Lindsay R. (author)
- Malmö University,Malmö universitet,Institutionen för materialvetenskap och tillämpad matematik (MTM)
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- Asthagiri, Aravind (author)
- Ohio State Univ, William G Lowrie Chem & Biomol Engn, Columbus, OH 43210 USA.,Ohio State University
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- Weaver, Jason F. (author)
- Univ Florida, Dept Chem Engn, Gainesville, FL 32611 USA.,University of Florida
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Univ Florida, Dept Chem Engn, Gainesville, FL 32611 USA University of Florida (creator_code:org_t)
- 2021-04-09
- 2021
- English.
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In: ACS Catalysis. - : American Chemical Society (ACS). - 2155-5435. ; 11:9, s. 5004-5016
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http://dx.doi.org/10...
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https://urn.kb.se/re...
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https://doi.org/10.1...
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Abstract
Subject headings
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- Continuous exposure to methane causes IrO2 (110) films on Ir(100) to undergo extensive reduction at temperatures from 500 to 650 K. Measurements using in situ X-ray photoelectron spectroscopy (XPS) confirm that CH4 oxidation on IrO2 (110) converts so-called bridging oxygen atoms (O-br) at the surface to HObr groups while concurrently removing oxygen from the oxide film. Reduction of the IrO2 (110) film by methane is mildly activated as evidenced by an increase in the initial reduction rate as the temperature is increased from 500 to 650 K. The XPS results show that subsurface oxygen efficiently replaces O-br atoms at the IrO2 (110) surface during CH4 oxidation, even after the reduction of multiple layers of the oxide film, and that metallic Ir gradually forms at the surface as well. The isothermal rate of IrO2 (110) reduction by methane decreases continuously as metallic Ir replaces surface IrO2 (110) domains, demonstrating that IrO2 (110) is the active phase for CH4 oxidation under the conditions studied. A key finding is that the replacement of O-br atoms with oxygen from the subsurface is efficient enough to preserve IrO2 (110) domains at the surface and enable CH4 to reduce the similar to 10-layer IrO2 (110) films nearly to completion. In agreement with these observations, density functional theory calculations predict that oxygen atoms in the subsurface layer can replace O-br atoms at rates that are comparable to or higher than the rates at which O-br atoms are abstracted during CH4 oxidation. The efficacy with which oxygen in the bulk reservoir replenishes surface oxygen atoms has implications for understanding and modeling catalytic oxidation processes promoted by IrO2 (110).
Subject headings
- TEKNIK OCH TEKNOLOGIER -- Materialteknik (hsv//swe)
- ENGINEERING AND TECHNOLOGY -- Materials Engineering (hsv//eng)
- NATURVETENSKAP -- Kemi -- Fysikalisk kemi (hsv//swe)
- NATURAL SCIENCES -- Chemical Sciences -- Physical Chemistry (hsv//eng)
- NATURVETENSKAP -- Kemi -- Oorganisk kemi (hsv//swe)
- NATURAL SCIENCES -- Chemical Sciences -- Inorganic Chemistry (hsv//eng)
Keyword
- ambient-pressure X-ray photoelectron spectroscopy
- methane activation
- metal oxide
- alkane
- methane oxidation
- iridium
- IrO2
- DFT
- alkane
- ambient-pressure X-ray photoelectron spectroscopy
- DFT
- iridium
- IrO
- metal oxide
- methane activation
- methane oxidation
Publication and Content Type
- ref (subject category)
- art (subject category)
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