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Fundamental Understanding of the Di-Air System: The Role of Ceria in NOx Abatement
- Source :
- Topics in Catalysis, 59(10-12)
- Publication Year :
- 2016
-
Abstract
- Temporal analysis of product (TAP) is used to investigate the effectiveness of CO, C3H6, and C3H8 in the reduction of a La–Zr doped ceria catalyst and NO reduction into N2 over this pre-reduced catalyst. Hydrocarbons are found to be substantially more effective in the reduction of this catalyst at high temperature (above 500 °C) as compared to CO. NO decomposes over oxygen anion defects created upon catalyst reduction. Deposited carbon, in case the catalyst is reduced by C3H6 or C3H8, acts as a delayed or stored reductant and is not directly involved in NO reduction. Instead the oxidation of deposited carbon by an oxygen species derived from lattice oxygen (re)creates the oxygen anion defects active in NO reduction. In situ Raman, in which NO is flown over C3H6 pre-reduced La–Zr doped ceria at 560 °C, additionally shows that re-oxidation of the La–Zr doped ceria catalyst starts prior to the oxidation of deposited carbon, which confirms our TAP findings that firstly NO re-oxidized the La–Zr doped ceria catalyst and that secondly the oxidation of deposited carbon only commences at a higher ceria oxidation state. These findings create a new perspective on the operating principle of Toyota’s Di-Air system.
- Subjects :
- inorganic chemicals
Materials science
Chemistry(all)
Hydrocarbon oxidation
Inorganic chemistry
chemistry.chemical_element
02 engineering and technology
010402 general chemistry
01 natural sciences
Oxygen
Catalysis
Ion
symbols.namesake
Ceria
Oxidation state
Di-air
Lattice oxygen
NO reduction
Doping
General Chemistry
021001 nanoscience & nanotechnology
0104 chemical sciences
chemistry
symbols
0210 nano-technology
Raman spectroscopy
Carbon
TAP
Subjects
Details
- Language :
- English
- ISSN :
- 10225528
- Database :
- OpenAIRE
- Journal :
- Topics in Catalysis, 59(10-12)
- Accession number :
- edsair.doi.dedup.....3e22bd18d1ccfa9db022d820a9e4f812