Monolith substrate, method for producing monolith substrate, and exhaust gas purification catalyst comprising monolith substrate

1. A monolith substrate comprising an alumina-ceria-zirconia composite oxide and alumina.

2. The monolith substrate according to claim 1 , wherein a content of the alumina-ceria-zirconia composite oxide is 8% by weight to 60% by weight relative to a total weight of the monolith substrate.

3. The monolith substrate according to claim 1 , wherein a content of the alumina is 40% by weight or more relative to a total weight of the monolith substrate.

4. The monolith substrate according to claim 1 , which further comprises a ceria-zirconia composite oxide.

5. The monolith substrate according to claim 4 , wherein a weight ratio of ceria in the alumina-ceria-zirconia composite oxide (CeO 2 (ACZ)) relative to the ceria in the alumina-ceria-zirconia composite oxide and ceria in the ceria-zirconia composite oxide (CeO 2 (ACZ+CZ)) (i.e., CeO 2 (ACZ)/CeO 2 (ACZ+CZ)) is 0.1 or more.

6. A method for producing the monolith substrate according to claim 1 comprising:

a step of mixing alumina-ceria-zirconia composite oxide particles, alumina particles, an alumina binder, and a solvent to prepare a mixture;

a step of molding the mixture to prepare a monolith substrate molding; and

a step of drying and firing the monolith substrate molding to produce the monolith substrate.

7. The method according to claim 6 , wherein a crystallite diameter of a ceria-zirconia composite oxide in the alumina-ceria-zirconia composite oxide particles is 30 nm or smaller.

8. The method according to claim 6 , wherein a specific surface area of the alumina-ceria-zirconia composite oxide particles determined by BET is 30 m 2 /g or larger.

9. The method according to claim 6 , wherein a specific surface area of the alumina particles determined by BET is 40 m 2 /g to 200 m 2 /g.

10. An exhaust gas purifying catalyst comprising the monolith substrate according to claim 1 and noble metal particles.