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- BOG, T, et al.
(författare)
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Oxygen storage material production useful in exhaust gas cleaning catalyst, involves mixing aqueous solution of cerium oxide precursor with aqueous solution of precursor of oxide of metal, and adding first precipitation agent to mixture.
- 2003
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Patent (populärvet., debatt m.m.)abstract
- NOVELTY - Oxygen storage material production comprises mixing aqueous solution of cerium oxide precursor with aqueous solution of precursor of oxide of metal to form mixture, adding first precipitation agent to mixture to form aqueous suspension containing precipitate, separating precipitate from suspension, drying and calcining precipitate. The oxygen storage material comprises cerium oxide and second oxide of a metal. The metal is alkaline earth metal, rare earth metal, zirconium, zinc, cobalt, copper and/or manganese. USE - The method is useful for producing oxygen storage material useful in exhaust gas cleaning catalyst for purifying exhaust gases of internal combustion engines especially of stoichiometrically operated otto engines. ADVANTAGE - The method provides catalyst that shows excellent activity for purifying harmful pollutant like carbon monoxide, nitrogen oxides, and hydrocarbons. The oxygen storage materials are able to store oxygen in oxidizing atmosphere or release oxygen under reducing conditions, respectively. The oxygen storage material has high specific surface area after thermal aging and improved oxygen storage and release capacity under dynamic exhaust conditions. The storage material shows unprecedented high oxygen storage capacity and excellent dynamic properties with respect to oxygen storage and release compared to conventional materials. DESCRIPTION OF DRAWING(S) - The figure shows setup of precipitation reactor. Precipitation reactor (1) Hydrolysis reactor (2) Tubular flow reactor (3) Precipitation solution (4) Feed (5) Mixer (7) Ph meter (8)
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| 2. |
- Hahlin, A, et al.
(författare)
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Ultrathin Co films on flat and vicinal Cu(111) surfaces: per atom determination of orbital and spin moments
- 2003
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Ingår i: Journal of Physics: Condensed Matter. - : IOP Publishing. - 0953-8984. ; 15:5, s. 573-586
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Konferensbidrag (refereegranskat)abstract
- We have performed x-ray magnetic circular dichroism, x-ray resonant magnetic scattering and scanning tunnelling microscopy measurements on ultrathin Co films deposited on flat and vicinal Cu(111). The range of film thickness varies between one and 25 monolayers. For the vicinal Cu(111), Co deposition below one monolayer leads to the formation of elongated islands preferentially oriented along the step edges. These islands extend over lateral length scales of up to several thousand angstroms. For the thicker films we still observe that the vicinal surface leads to the occurrence of a preferential uniaxial growth direction. No such preferential growth direction can be identified for the flat surface. In correlation to the Co growth we observe an increase of both the orbital and the spin moment per Co atom on vicinal Cu(111) of about 25% versus what was observed for Co on flat Cu(111). This enhancement is observed in both the x-ray absorption and the reflectivity measurements. Similar to what was earlier reported for Co on Cu(100) we also observe for the case Co on Cu(111) an increase in the ratio m(l)/m(s), (orbital to spin moments) of 40% for thin Co films. In contrast to what has been reported for Co films on flat and vicinal Cu(100) we do not observe any major variations in the occupancy of the Co 3d states for Co grown on the vicinal Cu(111) surface.
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