Mesoporous silica/ceria-silica composite and method for preparing same

Patent metadata

Field	Value
Publication number	US-9828295-B2
Application number	US-201415102261-A
Country	US
Kind code	B2
Filing date	Aug 12, 2014
Priority date	Feb 10, 2014
Publication date	Nov 28, 2017
Grant date	Nov 28, 2017

Abstract

The present invention relates to a mesoporous silica/ceria-silica composite and a method for preparing a mesoporous composite and, more specifically, to a mesoporous silica/ceria-silica composite which is composed of mesoporous silica having a hexagonal or cubic structure and ceria having a hexagonal structure provided on a surface and pores of the mesoporous silica, the oxidation state of the ceria being Ce 4+ and Ce 3+ .

First claim

The invention claimed is:

1. A mesoporous silica/ceria-silica composite comprising a mesoporous silica having a hexagonal structure or a cubic structure and a ceria having the hexagonal structure and provided on a surface and in a pore of the mesoporous silica, wherein oxidation states of the ceria are Ce 4+ and Ce 3+ ,
wherein, in the oxidation states of the ceria, the Ce 3+ has a content of 10.2 mole % to 23.8 mole % based on a total cerium, and the Ce 4+ has a content of 76.2 mole % to 89.8 mole % based on the total cerium.

2. The mesoporous silica/ceria-silica composite of claim 1 , wherein a mole ratio of Ce of the ceria to Si of the silica is in a range of 0.001 to 0.5.

3. The mesoporous silica/ceria-silica composite of claim 1 , wherein the mesoporous silica has a pore volume of 0.20 cm 3 /g to 0.40 cm 3 /g.

4. The mesoporous silica/ceria-silica composite of claim 1 , wherein the mesoporous silica/ceria-silica composite has a BET specific surface area of 250 m 2 /g to 600 m 2 /g.

5. A method of preparing a mesoporous silica/ceria-silica composite, the method comprising:
mixing and stirring a cationic surfactant, a silica precursor, and a cerium precursor;
preparing the mesoporous silica/ceria-silica composite by calcining a mixed solution after performing a hydrothermal reaction for the mixed solution; and
reducing the prepared mesoporous silica/ceria-silica composite,
wherein the reducing is performed at a temperature of 850° C. to 900° C. for 3 hours to 6 hours,
wherein a structure of mesoporous silica/ceria-silica composite is stable while the reducing is performed.

6. The method of claim 5 , wherein the cationic surfactant includes hexadecyl trimethyl ammonium bromide (CTAB) or hexadecyl trimethyl ammonium chloride (CTACl).

7. The method of claim 5 , wherein the silica precursor includes tetraethyl orthosilicate (TEOS) or tetramethyl orthosilicate (TMOS).

8. The method of claim 5 , wherein the cerium precursor includes one selected from the group consisting of cerium hydroxide (Ce(OH) 4 ), cerium nitrate (Ce(NO 3 ) 3 ), and cerium sulfate (Ce 2 (SO 4 ) 3 , Ce(SO 4 ) 2 ).

9. The method of claim 5 , wherein a mole ratio of the cerium precursor to the silica precursor is in a range of 0.001 to 0.5.

10. The method of claim 5 , wherein the stirring is performed at a rate of 200 rpm to 600 rpm for 30 min. to 1440 min.

11. The method of claim 5 , wherein the hydrothermal reaction is performed at a temperature of 80° C. to 120° C. for 20 hours to 48 hours.

12. The method of claim 5 , wherein the calcining is performed under air at a temperature of 500° C. to 600° C. for 4 hours to 6 hours.

13. A mesoporous silica/ceria-silica composite comprising a mesoporous silica having a hexagonal structure or a cubic structure and a ceria having the hexagonal structure and provided on a surface and in a pore of the mesoporous silica,
wherein the ceria is reduced through heat treatment and the ceria is present in oxidation states of Ce 3+ , and
wherein the ceria has diffraction patterns which are matched with that of Ce 4.667 Si 3 O 13 in a structure similar to an apatite structure having a hexagonal unit lattice.

14. The mesoporous silica/ceria-silica composite of claim 13 , wherein the Ce 3+ has a content of 10.2 to 100 mole % based on a total cerium.

Assignees

• Found Res & Business Seoul Nat Univ Sci & Tech

Inventors

• Cho Eun-Bum
• Yim Seung-Hyuk

Classifications

• C04B2235/5409

  expressed by specific surface values · CPC title

• C04B2235/443

  Nitrates or nitrites · CPC title

• C04B2235/441

  Alkoxides, e.g. methoxide, tert-butoxide · CPC title

• C04B35/14 Primary

  based on silica · CPC title

• C01P2006/16

  Pore diameter · CPC title