Aluminium and Zirconium-Based Mixed Oxide

Patent metadata

Field	Value
Publication number	US-2025041833-A1
Application number	US-202218715222-A
Country	US
Kind code	A1
Filing date	Nov 24, 2022
Priority date	Dec 1, 2021
Publication date	Feb 6, 2025
Grant date	—

Abstract

The present invention relates to a mixed oxide of aluminium, of zirconium, of cerium, of lanthanum and optionally of at least one rare-earth metal other than cerium and other than lanthanum that makes it possible to repair a catalyst that retains, after severe ageing, a good thermal stability and a good catalytic activity. The invention also relates to the process for preparing this mixed oxide and also to a process for treating exhaust gases from internal combustion engines using a catalyst prepared from this mixed oxide. The mixed oxide exhibits at least one of the 3 characteristics (i), (ii), (iii) below:—(i) Δ is lower than 82.0%, Δ being calculated by the following formula: Δ=(S950° C./3 h−S1200° C./5 h)/S950° C./3 h×100; (ii) Δ* is lower than 55.0%, Δ* being calculated by the following formula: Δ*=(S950° C./3 h−S1100® C/5 h)/S950° C./3 h×100; (iii) S1200° C./5 h is strictly higher than 15.0 m2/g (>15.0 m2/g).

First claim

1 . A mixed oxide of aluminium, of zirconium, of lanthanum and optionally of at least one rare-earth metal other than cerium and other than lanthanum (denoted REM), the proportions by weight of these elements being as follows:
between 20.0 wt % and 45.0 wt % of aluminium, between 25.0 wt % and 40.0 wt %, or between 25.0 wt % and 35.0 wt %; between 1.0 wt % and 15.0 wt % of lanthanum, between 1.0 wt % and 10.0 wt %, between 1.0 wt % and 7.0 wt %, or between 2.0 wt % and 7.0 wt %; between 0 and 10.0 wt %, between 1.0 wt % and 10.0 wt %, between 10.0 wt % and 7.0 wt %, or between 2.0 and 7.0% for the rare-earth metal other than cerium and other than lanthanum, on condition that if the mixed oxide comprises more than one rare-earth metal other than cerium and other than lanthanum, this proportion applies to each of these rare-earth metals optionally wherein the total proportion of the rare-earth metal other than cerium and other than lanthanum is less than 25.0 wt %, or less than 20%; between 50.0 wt % and 70.0 wt, or between 55.0 wt % and 65.0 wt % of zirconium;
these proportions being expressed as oxide equivalent with respect to the total weight of the mixed oxide,
wherein after calcination in air at 1100° C. for 5 hours, the specific surface area (BET) of the mixed oxide is at least 25.0 m 2 /g;
and in that after calcination in air at 950° C. for 3 hours, the porosity of the mixed oxide determined by N 2 porosimetry is such that:
in the domain of the pores with a size lower than 100 nm, the porogram of the mixed oxide exhibits a peak which is located at a diameter D p, 950° C./3 h between 15 and 30 nm;
the ratio V <40 nm, 950° C./3 h /V total, 950° C./3 h is greater than or equal to 0.80, greater than or equal to 0.85, or greater than or equal to 0.90;
V total, 950° C./3 h is greater than or equal to 0.35 ml/g, greater than or equal to 0.40 ml/g, or greater than or equal to 0.45 ml/g;
V <40 nm, 950° C./3 h , V total, 950° C./3 h denoting respectively the pore volume for the pores with a size lower than 40 nm and the total pore volume of the mixed oxide after calcination in air at 950° C. for 3 hours;

the mixed oxide being further characterized by one or more of the three characteristics (i), (ii), (iii) below:
(i) Δ is lower than 82.0%, Δ being calculated by the following formula:

Δ
=

(

S

950
⁢
°
⁢

C
.

/
3

⁢

h

-

S

1200
⁢
°
⁢

C
.

/
5

⁢

h

)

/

S

950
⁢
°
⁢

C
.

/
3

⁢

h

×
100

;

(ii) Δ* is lower than 55.0%, Δ* being calculated by the following formula:

Δ
*

=

(

S

950
⁢
°
⁢

C
.

/
3

⁢

h

-

S

1100
⁢
°
⁢

C
.

/
5

⁢

h

)

/

S

950
⁢
°
⁢

C
.

/
3

⁢

h

×
100

;

(iii) S 1200° C./5 h is strictly higher than 15.0 m 2 /g;
wherein S 950° C./3 h , S 1100° C./5 h and S 1200° C./5 h denotes respectively the BET specific surface areas for the mixed oxide after calcination in air at respectively 950° C. for 3 hours, 1100° C. for 5 hours and 1200° C. for 5 hours.

2 . (canceled)

3 . The mixed oxide according to claim 1 , characterized in that after calcination in air at 950° C. for 3 hours, the porogram of the mixed oxide exhibits in the domain of the pores with a size lower than 100 nm, a single peak which is located at diameter D p, 950° C./3 h .

4 . The mixed oxide according to claim 1 further comprising hafnium.

5 - 7 . (canceled)

8 . The mixed oxide according to claim 1 wherein the mean size of the crystallites of the crystalline phase based on zirconium oxide is strictly higher than 10 nm and/or lower than 25 nm or lower than 20 nm, this size bein

Assignees

• Rhodia Operations

Inventors

• Ohtake Naotaka
• Nishimura Kaoru
• Sasaki Toshihiro
• Shozui Tetsuya

Classifications

• C01P2006/12

  Surface area · CPC title

• B01J35/45

  Nanoparticles · CPC title

• C01G99/006

  Compounds containing a metal not provided for elsewhere in this subclass, with or without oxygen or hydrogen, and containing two or more other elements (C01G99/003 takes precedence) · CPC title

• C01F7/78

  Compounds containing aluminium, with or without oxygen or hydrogen, and containing two or more other elements (aluminates C01F7/02; compounds containing aluminium, fluorine and alkali or alkaline earth metals C01F7/54; nitrates containing other cations besides aluminium C01F7/66; sulfides, sulfites or sulfates containing other cations besides aluminium C01F7/70 - C01F7/74) · CPC title

• B01J35/70

  characterised by their crystalline properties, e.g. semi-crystalline (catalysts comprising carbon B01J21/18; molecular sieves B01J29/00) · CPC title