Alcohol synthesis from carbon monoxide and hydrogen over MoS sub 2 -based catalysts
The synthesis of linear C{sub 1}-C{sub 4} alcohols from synthesis gas (CO + H{sub 2}) over alkali-promoted MoS{sub 2}-based catalysts has been studied. A large doping level of alkali was essential for the formation of alcohols rather than hydrocarbons over these catalysts. The indispensable presence of the alkali salt promoter for alcohol synthesis was due to the bifunctionality of the catalyst in which the alkali activates CO and MoS{sub 2} activates H{sub 2}. Injection of {sup 13}C-labeled CH{sub 3} OH into the synthesis gas stream over alkali-promoted MoS{sub 2}-based catalysts and analysis by {sup 13}C NMR spectroscopy of the condensable products, accompanied by mass spectrometric analysis of light gaseous products, demonstrated that the alcohol chain growth occurred via a classical CO insertion mechanism, and that methane is a secondary product that is formed from an alkyl moiety generated from a C{sub 1}-oxygenated precursor. The addition of cobalt to the alkali-doped MoS{sub 2} catalyst greatly enhanced the rate of the C{sub 1} {yields} C{sub 2} growth step so that ethanol became the dominant product. The alkali-doped MoS{sub 2} catalysts prior to and after attaining their work state were fully characterized by XPS, XRD, STEM, and surface area measurements. Pretreatment (400 C, 2% H{sub 2}/N{sub 2} 1 h) of the catalysts induces not only reduction of surface species such as Mo(VI) and SO{sub 4}{sup 2{minus}} detected on the fresh catalysts, but also dispersion of the cesium on the MoS{sub 2} surface. The oxidation states of S and Mo in the tested catalysts correspond to those of MoS{sub 2}. XPS intensity equations were derived from geometrical models of the catalyst surface to determine the degree of dispersion and/or segregation of Cs on the MoS{sub 2} surface.
- Research Organization:
- Lehigh Univ., Bethlehem, PA (USA)
- OSTI ID:
- 6763797
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
10 SYNTHETIC FUELS
ALCOHOLS
SYNTHESIS
CARBON MONOXIDE
HYDROGENATION
MOLYBDENUM SULFIDES
CATALYTIC EFFECTS
ADDITIVES
ALKALI METALS
CARBON 13
CATALYSIS
CATALYSTS
CESIUM
CHEMICAL REACTION KINETICS
COBALT
CRYSTAL STRUCTURE
DOPED MATERIALS
ETHANOL
MASS SPECTROSCOPY
METHANATION
NUCLEAR MAGNETIC RESONANCE
PHOTOELECTRON SPECTROSCOPY
REDUCTION
SCANNING ELECTRON MICROSCOPY
SURFACE AREA
SURFACE PROPERTIES
TRACER TECHNIQUES
TRANSMISSION ELECTRON MICROSCOPY
X-RAY DIFFRACTION
X-RAY SPECTROSCOPY
CARBON COMPOUNDS
CARBON ISOTOPES
CARBON OXIDES
CHALCOGENIDES
CHEMICAL REACTIONS
COHERENT SCATTERING
DIFFRACTION
ELECTRON MICROSCOPY
ELECTRON SPECTROSCOPY
ELEMENTS
EVEN-ODD NUCLEI
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LIGHT NUCLEI
MAGNETIC RESONANCE
MATERIALS
METALS
MICROSCOPY
MOLYBDENUM COMPOUNDS
NUCLEI
ORGANIC COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
REACTION KINETICS
REFRACTORY METAL COMPOUNDS
RESONANCE
SCATTERING
SPECTROSCOPY
STABLE ISOTOPES
SULFIDES
SULFUR COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
TRANSITION ELEMENTS
010408* - Coal
Lignite
& Peat- C1 Processes- (1987-)
100200 - Synthetic Fuels- Production- (1990-)