| 简介 |
FIELD : chemistry.
SUBSTANCE : invention is intended for use in three-way catalysts for cleaning exhaust gases of automobiles. Method of producing oxide compositions of cerium-zirconium involves preparing a total solution with concentration of 10 to 100 g/dm3 in terms of the final composition, containing soluble salts of zirconium, cerium, as well as one or more rare-earth elements selected from yttrium, lanthanum and neodymium. Precipitation of hydroxides at controlled pH and temperature is carried out by simultaneous supply of common solution and the main compound into the reaction volume, which is a mixture of distilled water and an auxiliary surfactant selected from carboxylic acids, in amount of 20 to 100 % of the weight of the final oxide composition. PH value during deposition is maintained at level of 8 to 10 units. Reaction volume temperature is maintained from 40 to 80 °C. After sedimentation, the obtained suspension is filtered, dried and annealed at 500–900 °C.
EFFECT : invention reduces the number of steps and increases specific surface area of the product and thus increases resistance of the oxide composition to high temperatures.
1 cl, 1 dwg, 5 ex |
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