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1. (WO1998051617) LOW TEMPERATURE PRODUCTION OF METAL OXIDES
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Claims

1. A process for the preparation of a metal oxide gel product, which process includes the steps of:
(a) heating a mixture of a wet hydrous metal oxide and either:
(i) a hydrolytic acid; or
(ii) a metal salt;
to form a wet gel;
(b) heating die wet gel under a controlled pressure atmosphere to the decomposition temperature of the acid or salt as appropriate; and

(c) removing any non-dispersible product.

2. A process as claimed in Claim 1 , characterised in mat die metal salt is a metal nitrate.

3. A process as claimed in any one of the preceding claims, characterised in that the wet gel is formed by heating the wet hydrous metal oxide mixture to between room temperature and 120 °C.

4. A process as claimed in any one of the preceding claims, characterised in that die wet gel is formed by heating the wet hydrous metal oxide for between 1 and 24 hours.

5. A process as claimed in any one of the preceding claims, characterised in mat the controlled atmosphere is provided by means of a pressure reactor vessel.

6. A process as claimed in any one of the preceding claims, characterised in that wet gel is heated for between about 20 and 75 minutes.

7. A process as claimed in any one of the preceding claims, characterised in that wet gel is heated at a heating rate of between 175 and 225 °C per hour.

8. A process as claimed in any one of the preceding claims, characterised in that non-dispersible product is removed by:
(a) dispersing die metal oxide gel formed by heating the wet gel, in a solvent to form a sol;
(b) removing any non-dispersible sediment; and
(c) drying the sol.

9. A process as claimed in Claim 8, characterised in mat die metal oxide gel is cooled under a controlled atmosphere to below 60 °C before dispersing.

10. A process as claimed in Claim 8 or Claim 9, characterised in that the solvent is aqueous.

11. A process as claimed in any one of Claims 8 to 10, characterised in mat the sol is dried at between 20 and 125 °C.

12. A product obtainable by a process according to any one of Claims 1 to 11.

13. A substantially dispersible nanocrystalline metal oxide gel product.

14. A process for the formation of a solid solution of a metal oxide which process comprises heating a product according to Claim 12 or Claim 13.

15. The use of a product according to Claim 12 or Claim 13 in the manufacture of a solid solution of a metal oxide.

16. A process for the formation of a catalyst, which process comprises dispersing a product according to Claim 12 or Claim 13 onto a catalyst support.

17. The use of a product as claimed in Claim 12 or Claim 13 in the manufacture of a catalyst.

18. A catalyst comprising a product according to Claim 12 or Claim 13 and a catalyst support.

19. The use of a product as claimed in Claim 12 or Claim 13 in the manufacture of a fuel cell.

20. The use of a product as claimed in Claim 12 or Claim 13 to coat or impregnate a substrate.

21. A layered material comprising a substrate coated with a product as claimed in Claim 12 or Claim 13.