Monolithic rare earth oxide aerogels

Patent metadata

Field	Value
Publication number	US-2017267925-A1
Application number	US-201615073400-A
Country	US
Kind code	A1
Filing date	Mar 17, 2016
Priority date	Mar 17, 2016
Publication date	Sep 21, 2017
Grant date	—

Abstract

Disclosed here is a method for making a monolithic rare earth oxide (REO) aerogel, comprising: preparing a reaction mixture comprising at least one rare earth metal nitrate, at least one epoxide, at least one base catalyst, and at least one organic solvent; curing the mixture to produce a wet gel; drying the wet gel to produce a dry gel; and thermally annealing the dry gel to produce the monolithic REO aerogel. Also disclosed is an REO aerogel comprising a network of REO nanostructures, wherein the REO aerogel is a monolith having at least one lateral dimension of at least 1 cm, wherein the REO aerogel has a density of about 40-500 mg/cm 3 and/or a BET surface area of at least about 20 m 2 /g, and wherein the REO aerogel is substantially free of oxychloride.

First claim

What is claimed is:

1 . A method for making a monolithic rare earth oxide (REO) aerogel, comprising:
preparing a reaction mixture comprising at least one rare earth metal nitrate, at least one epoxide, at least one base catalyst, and at least one organic solvent; curing the mixture to produce a wet gel; drying the wet gel to produce a dry gel; and thermally annealing the dry gel to produce the monolithic REO aerogel.

2 . The method of claim 1 , wherein the reaction mixture comprises at least two different rare earth metal nitrates.

3 . The method of claim 1 , wherein the reaction mixture is substantially free of chloride.

4 . The method of claim 1 , wherein the base catalyst is selected from the group consisting of ammonium carbonate, sodium carbonate, sodium hydroxide, ammonium hydroxide, and ammonia vapor.

5 . The method of claim 1 , wherein the base catalyst is ammonium carbonate.

6 . The method of claim 1 , wherein the epoxide is propylene oxide.

7 . The method of claim 1 , wherein the organic solvent is alcohol.

8 . The method of claim 1 , wherein the reaction mixture is cured at a temperature of about 50°-100° C.

9 . The method of claim 1 , wherein the drying step comprises washing in acetone or dry alcohol.

10 . The method of claim 1 , wherein the drying step comprises supercritical drying or ambient drying.

11 . The method of claim 1 , wherein the dry gel is thermally annealed in air or in an inert atmosphere at a temperature of about 500° C. or higher.

12 . The method of claim 1 , wherein the REO aerogel is produced in less than about 120 hours starting from the curing step to completion of the thermal annealing step.

13 . An REO aerogel obtained by the method of claim 1 .

14 . The REO aerogel of claim 13 , wherein the REO aerogel is a monolith having at least one lateral dimension of at least 1 cm.

15 . The REO aerogel of claim 13 , wherein the REO aerogel has a density of about 40-500 mg/cm 3 and/or a BET surface area of at least about 20 m 2 /g.

16 . The REO aerogel of claim 13 , wherein the REO aerogel comprises at least about 20 at. % of lanthanide.

17 . The REO aerogel of claim 13 , wherein the REO aerogel is a crystalline material.

18 . The REO aerogel of claim 13 , wherein the REO aerogel is photoluminescent.

19 . The REO aerogel of claim 13 , wherein the REO aerogel is substantially free of oxychloride.

20 . An REO aerogel comprising a network of REO nanostructures, wherein the REO aerogel is a monolith having at least one lateral dimension of at least 1 cm, wherein the REO aerogel has a density of about 40-500 mg/cm 3 and/or a BET surface area of at least about 20 m 2 /g, and wherein the REO aerogel is substantially free of oxychloride.

Assignees

• L Livermore Nat Security Llc

Inventors

• Worsley Marcus A
• Gash Alexander E
• Reibold Robert A

Classifications

• C01F17/32

  oxide or hydroxide being the only anion, e.g. NaCeO2 or MgxCayEuO · CPC title

• C01P2006/12

  Surface area · CPC title

• C01P2006/60

  Optical properties, e.g. expressed in CIELAB-values · CPC title

• C04B38/009

  Porous or hollow ceramic granular materials, e.g. microballoons (C04B18/027, C04B20/002 take precedence) · CPC title

• C01P2006/80

  Compositional purity · CPC title