Catalyst and semiconductor studies involving oxidized rare earth intermetallic compounds. [Visible radiation]
The intermetallic compounds (LaNi/sub 5/, CeNi/sub 5/, Ce/sub 2/Ni/sub 17/, TbNi/sub 5/, ZrNi/sub 5/, LaCo/sub 5/ ThCo/sub 5/ and CeCo/sub 5/) were oxidized with nitric oxide (NO), synthesis gas (SG) and oxygen (O/sub 2/). Most of these intermetallic compounds react readily with the oxidizers and were transformed into a mixture of transition metal and rare earth oxide for ThO/sub 2/) during the oxidation processes. Samples were also prepared by a freeze-drying method. The catalytic activity of these materials for synthesis gas conversion was measured with a single pass microreactor operating at 1 atm total pressure, and the major products were CH/sub 4/, CO/sub 2/, C/sub 2/H/sub 4/, C/sub 2/H/sub 6/ and H/sub 2/O. The product distribution indicated that the formation of methane is favored for most of the catalysts. CeCo/sub 5/ and LaCo/sub 5/ oxidized with O/sub 2/ were found to have higher olefin to paraffin ratio than the other catalysts. Carbon deposition occurs on the oxidized Co compound and ZrNi/sub 5/ during the catalytic reaction. The preparation of polycrystalline rare earth iron oxide electrodes by heating the rare earth (R) iron compounds (RFe/sub 2/, RFe/sub 3/, R/sub 2/Fe/sub 17/ and R/sub 6/Fe/sub 23/) in air in the flame of a Fisher burner is reported. Iron oxide and titanium oxide are also prepared by heating Fe and Ti metal in air for comparison. The current-voltage (I-V) properties of these materials are measured in aqueous solution of 1 M NaOH. The flatband potentials (V/sub fb/) are determined with respect to a fixed potential (SCE) extrapolating to zero current in I-V curves. Photoelectrolysis of water occurs at these electrodes, resulting in the evolution of oxygen (O/sub 2/) from the RFeO/sub x/ electrodes and hydrogen from the Pt electrode. Most of these electrodes are found to be stable under experimental conditions and anodic photocurrents are generated by light energy greater than the band gap energy (E/sub g/).
- Research Organization:
- Pittsburgh Univ., PA (USA)
- OSTI ID:
- 6072353
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
CERIUM ALLOYS
CATALYTIC EFFECTS
ELECTROCHEMISTRY
OXIDATION
COBALT ALLOYS
IRON ALLOYS
LANTHANUM ALLOYS
CATALYSTS
PHOTOELECTROLYSIS
METHANATION
NICKEL ALLOYS
TERBIUM ALLOYS
THORIUM ALLOYS
WATER
ZIRCONIUM ALLOYS
CATALYSIS
INTERMETALLIC COMPOUNDS
NITRIC OXIDE
OXYGEN
SYNTHESIS GAS
TITANIUM OXIDES
ACTINIDE ALLOYS
ALLOYS
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISTRY
ELECTROLYSIS
ELEMENTS
FLUIDS
GASES
HYDROGEN COMPOUNDS
LYSIS
NITROGEN COMPOUNDS
NITROGEN OXIDES
NONMETALS
OXIDES
OXYGEN COMPOUNDS
RARE EARTH ALLOYS
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
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