| 摘要 |
FIELD: chemistry.SUBSTANCE: invention relates to a composition based on cerium oxide and zirconium oxide having special porosity, which can be used in catalyst systems for treating exhaust gases. The composition is based on cerium oxide and zirconium oxide containing at least 30 wt % cerium oxide which, after calcination at temperature of 900°C for 4 hours, has two types of pore distribution, the diameters of which, for the first type of distribution, lie in the range from 5 nm to 15 nm for a composition having cerium oxide content of 30% to 65%, or from 10 nm to 20 nm for a composition having cerium oxide content higher than 65% and, for the second type of distribution, in the range from 45 nm to 65 nm for a composition having a cerium oxide content of 30% to 65% or from 60 nm to 100 nm for a composition having cerium oxide content higher than 65%. The method of producing the composition includes steps of: forming a first liquid medium containing a zirconium compound, a cerium (III) compound, sulphate ions, an oxidising agent and, optimally, a compound of a rare-earth element other than cerium; bringing the medium into contact with a base, whereby a precipitate is formed; separating and washing the precipitate; suspending the precipitate in water and heat treatment of the obtained medium at temperature of 90°C; and separating and calcining the precipitate.EFFECT: composition has high specific surface area and provides good diffusion of gases.17 cl, 2 dwg, 2 tbl, 2 ex |
