CO{sub 2} reduction by group 6 transition metal suboxide cluster anions
- Department of Chemistry, Indiana University, 800 E. Kirkwood Avenue, Bloomington, Indiana 47405 (United States)
Reactions between small group 6 transition metal suboxide clusters, M{sub x}O{sub y}{sup -} (M={sup 98}Mo or {sup 186}W; x=1-4; y{<=}3x) and both CO{sub 2} and CO were studied in gas phase using mass spectrometric analysis of high-pressure, fast flow reaction products. Both Mo{sub 2}O{sub y}{sup -} and W{sub 2}O{sub y}{sup -} show evidence of sequential oxidation by CO{sub 2} of the form, M{sub 2}O{sub y}{sup -}+CO{sub 2}{yields}M{sub 2}O{sub y+1}{sup -}+CO for the more reduced species. Similar evidence is observed for the trimetallic clusters, although Mo{sub 3}O{sub 6}{sup -} appears uniquely unreactive. Lower mass resolution in the M{sub 4}O{sub y}{sup -} range precludes definitive product mass assignments, but intensity patterns suggest the continued trend of sequential oxidation of the more reduced end of the M{sub 4}O{sub y}{sup -} oxide series. Based on thermodynamic arguments, cluster oxidation by CO{sub 2} is possible if D{sub 0}(O-Mo{sub x}O{sub y}{sup -})>5.45 eV. Although simple bond energy analysis suggests that tungsten oxides may be more reactive toward CO{sub 2} compared to molybdenum oxides, this is not born out experimentally, suggesting that the activation barrier for the reduction of CO{sub 2} by tungsten suboxide clusters is very high compared to analogous molybdenum suboxide clusters. In reactions with CO, suboxides of both metal-based oxides show CO addition, with the product distribution being more diverse for Mo{sub x}O{sub y}{sup -} than for W{sub x}O{sub y}{sup -}. No evidence of cluster reduction by CO is observed.
- OSTI ID:
- 21559878
- Journal Information:
- Journal of Chemical Physics, Vol. 133, Issue 2; Other Information: DOI: 10.1063/1.3455220; (c) 2010 American Institute of Physics; ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
74 ATOMIC AND MOLECULAR PHYSICS
ANIONS
ATOMIC CLUSTERS
BINDING ENERGY
CARBON DIOXIDE
CARBON MONOXIDE
CHEMICAL ANALYSIS
ION-MOLECULE COLLISIONS
MASS RESOLUTION
MASS SPECTROSCOPY
MOLECULAR CLUSTERS
MOLYBDENUM
MOLYBDENUM 98
MOLYBDENUM OXIDES
OXIDATION
PRESSURE RANGE MEGA PA 10-100
REACTION KINETICS
REDUCTION
TUNGSTEN
TUNGSTEN 186
TUNGSTEN OXIDES
CARBON COMPOUNDS
CARBON OXIDES
CHALCOGENIDES
CHARGED PARTICLES
CHEMICAL REACTIONS
COLLISIONS
ELEMENTS
ENERGY
EVEN-EVEN NUCLEI
HEAVY NUCLEI
INTERMEDIATE MASS NUCLEI
ION COLLISIONS
IONS
ISOTOPES
KINETICS
METALS
MOLECULE COLLISIONS
MOLYBDENUM COMPOUNDS
MOLYBDENUM ISOTOPES
NUCLEI
OXIDES
OXYGEN COMPOUNDS
PRESSURE RANGE
PRESSURE RANGE MEGA PA
REFRACTORY METAL COMPOUNDS
REFRACTORY METALS
RESOLUTION
SPECTROSCOPY
STABLE ISOTOPES
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
TUNGSTEN COMPOUNDS
TUNGSTEN ISOTOPES