Method for the preparation of metal oxides in nanometric particle form
View Patent ↗A process is described for the synthesis of metal oxides in a nanometric particle form that cannot be easily obtained by conventional bulk synthesis techniques. The method makes use of Colloid Occluded Carbons (COC) and Colloid Imprinted Carbons (CIC) as reagents and as templating agents for the preparation of metal oxides in nanometric particle form. The nanometric particles are suitable useful in the field of chemical catalysis, particularly for petroleum refining when in porous form, and as sensors, optical wave guides, and coatings.
1. A process for forming a metal oxide composition in nanometric particle form which comprises:
(a) providing a colloid imprinted carbon (CIC) as a nanometric particle template;
(b) forming through a chemical reaction a metal oxide or a metal oxide precursor in the mesopores of the CIC template; and
(c) removing the CIC from the product of step (b) by heating the CIC in an oxidizing atmosphere to thereby remove the CIC and to produce the metal oxide in nanometric particle form.
2. The process of claim 1 wherein the metal component of the metal oxide is selected from the metallic elements of groups 1 through 15 of the periodic table, the lanthanide elements, the actinide elements, and mixtures thereof.
3. The process of claim 1 wherein the metal oxide is a zeolite.
4. The process of claim 1 wherein the metal oxide particles are selected from the group consisting of aluminas and silicas and mixtures thereof.
5. The process of claim 1 wherein the metal oxide nanometric particles are spherical and have a diameter of less than 100 nm.
6. The process of claim 1 wherein the metal oxide nanometric particles are a plate with a thickness of less than 100 nm.
7. The process of claim 1 wherein the metal oxide nanometric particles have a dimension of less than 100 nm in at least one dimension.
8. The process of claim 1 wherein the metal oxide nanometric particles aggregate to form larger agglomerates having dimensions greater than 100 nm.
9. The process of claim 1 wherein the CIC template is prepared from pitch tar.
10. The process of claim 1 wherein a metal alkoxide is chemically reacted in the mesopores of the CIC to form a metal oxide or a metal oxide precursor in nanometric particle form.
11. The process of claim 10 wherein the metal alkoxide is selected from the group consisting of a silicon alkoxide and an aluminum alkoxide.
12. The process of claim 1 wherein an aluminate, silicate or a mixture thereof is selected as a precursor to the metal oxide.
13. The process of claim 1 wherein the metal oxide is mesoporous.
14. A process for producing a metal oxide-carbon composite composition in which step (c) in claim 1 is eliminated.