| CPC B01J 23/63 (2013.01) [B01J 23/002 (2013.01); B01J 35/613 (2024.01); B01J 35/615 (2024.01); B01J 35/633 (2024.01); B01J 35/635 (2024.01); B01J 35/651 (2024.01); B01J 37/009 (2013.01); B01J 37/038 (2013.01); B01J 37/04 (2013.01); B01J 37/082 (2013.01); C01G 25/006 (2013.01); C01P 2006/12 (2013.01); C01P 2006/14 (2013.01); C01P 2006/16 (2013.01)] | 24 Claims |
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1. A mixed oxide comprising zirconium, cerium, lanthanum and optionally at least one rare-earth element other than cerium and other than lanthanum (RE) with the following composition:
between 18.0% and 70.0% by weight of cerium;
between 1.0% and 10.0% by weight of lanthanum;
up to 10.0% by weight of the at least one rare earth element(s) (RE(s)) other than cerium and other than lanthanum;
the remainder as zirconium;
the mixed oxide being in the form of particles exhibiting a d50 strictly higher than 2.5 μm and the proportions of the elements (Ce, La, RE, Zr) being given by weight of oxide relative to the mixed oxide as a whole, characterized in that:
it exhibits a specific surface area (BET) of at least 28 m2/g after calcination in air at 1100° C. for 4 hours;
the peak with the highest intensity in the domain of the pores with a pore size lower than 500 nm, is between 70 nm, this value being excluded, and 500 nm, and corresponds to a pore size Dp,1100° C./4 h; and
the peak with the highest intensity in the domain of the pores with a pore size lower than 500 nm is between 35 nm and 75 nm, and corresponds to a pore size Dp,900° C./4 h, and
it exhibits a total pore volume V500 nm,1100° C./4 h for the pores with a size lower than 500 nm, of at least 0.30 ml/g; wherein
the pore size Dp,1100° C./4 h and the total pore volume V500 nm,1100° C./4 h being determined by mercury porosimetry on the mixed oxide after calcination in air at 1100° C. for 4 hours and Dp,900° C./4 h, is determined by mercury porosimetry on a mixed oxide after calcination in air at 900° C. for 4 hours.
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3. The mixed oxide according to claim 1, consisting of a combination of the oxides of zirconium, of cerium, of lanthanum, optionally of at least one rare earth element other than cerium and other than lanthanum and optionally of hafnium, with the following composition:
between 18.0% and 70.0% by weight of cerium;
between 1.0% and 10.0% by weight of lanthanum;
up to 10.0% by weight of the rare earth element(s) (RE(s)) other than cerium and other than lanthanum;
a proportion of hafnium lower or equal to 2.0%;
the remainder as zirconium;
the mixed oxide being in the form of particles exhibiting a d50 strictly higher than
2.5 μm and the proportions of the elements (Ce, La, RE, Hf, Zr) being given by weight of oxide relative to the mixed oxide as a whole, characterized in that:
it exhibits a specific surface area (BET) of at least 28 m2/g after calcination in air at 1100° C. for 4 hours;
the peak with the highest intensity in the domain of the pores with a size lower than 500 nm corresponds to a pore size Dp,1100° C./4 h between 70 nm, this value being excluded, and 500 nm; and
the peak with the highest intensity in the domain of the pores with a pore size lower than 500 nm is between 35 nm and 75 nm, and corresponds to a pore size Dp,900° C./4 h, and
it exhibits a total pore volume V500 nm,1100° C./4 h for the pores with a size lower than 500 nm, of at least 0.30 ml/g;
wherein
the pore size Dp, 1100° C./4 h and the total pore volume V500 nm,1100° C./4 h being determined by mercury porosimetry on the mixed oxide after calcination in air at 1100° C. for 4 hours and Dp,900° C./4 h, is determined by mercury porosimetry on a mixed oxide after calcination in air at 900° C. for 4 hours.
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