Mechanism of the reaction of nitric oxide, ammonia, and oxygen over vanadia catalysts. 2. Isotopic transient studies with oxygen-18 and nitrogen-15
The mechanism of nitric oxide reduction with ammonia to form N/sub 2/, H/sub 2/O and N/sub 2/O both in the presence and in the absence of O/sub 2/ over the following series of catalysts, unsupported V/sub 2/O/sub 5/, V/sub 2/O/sub 5/ on TiO/sub 2/, V/sub 2/O/sub 5/ on SiO/sub 2//Al/sub 2/O/sub 3/, and V/sub 2/O/sub 5/ on Al/sub 2/O/sub 3/, has been investigated with the aid of labeled O/sub 2/ and labeled NH/sub 3/ at 400/sup 0/C. The behavior of ammonia was studied both in the presence and in the absence of O/sub 2/. The presence of labeled O/sub 2/ gives extra information about the product distribution and the reaction mechanism. Evidence is given that ammonia does not react with O/sub 2/ or O from any source during the reaction, but that nitrogen and nitrous oxide were produced by a reaction involving all three species, NO, NH/sub 3/, and/or O/sub 2/. Nitrous oxide and water are both formed at two different sites of the catalyst. A series of transient tracing studies were performed in a plug-flow reactor using /sup 15/NH/sub 3/ and /sup 18/O/sub 2/. Both /sup 15/NN and /sup 15/NNO were produced on the unsupported V/sub 2/O/sub 5/, V/sub 2/O/sub 5/ on TiO/sub 2/, V/sub 2/O/sub 5/ on SiO/sub 2//Al/sub 2/O/sub 3/, and V/sub 2/O/sub 5/ on Al/sub 2/O/sub 3/ with very high selectivities. The mechanism of the reaction of NO, NH/sub 3/, and O/sub 2/, proposed in a previous paper, is further evaluated on the basis of this new experimental evidence.
- Research Organization:
- Arnhem Institutions of the Dutch Electricity Utilities (Netherlands)
- OSTI ID:
- 5353173
- Journal Information:
- J. Phys. Chem.; (United States), Vol. 91:27
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
AMMONIA
CHEMICAL REACTIONS
NITRIC OXIDE
NITROGEN 15
ISOTOPE EFFECTS
OXYGEN
OXYGEN 18
VANADIUM OXIDES
CATALYTIC EFFECTS
ALUMINIUM OXIDES
CATALYSIS
CATALYSTS
EXPERIMENTAL DATA
SILICA
ALUMINIUM COMPOUNDS
CHALCOGENIDES
DATA
ELEMENTS
EVEN-EVEN NUCLEI
HYDRIDES
HYDROGEN COMPOUNDS
INFORMATION
ISOTOPES
LIGHT NUCLEI
MINERALS
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NITROGEN ISOTOPES
NITROGEN OXIDES
NONMETALS
NUCLEI
NUMERICAL DATA
ODD-EVEN NUCLEI
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
OXYGEN ISOTOPES
SILICON COMPOUNDS
SILICON OXIDES
STABLE ISOTOPES
TRANSITION ELEMENT COMPOUNDS
VANADIUM COMPOUNDS
400202* - Isotope Effects
Isotope Exchange
& Isotope Separation