1. A pillared clay comprising zirconium oxide pillars having a gallery height of .gtoreq.4 to .ltoreq.7 Angstroms wherein the clay is selected from the group consisting of swellable smectites and micas and said clay is capable of maintaining at least about 80% of said gallery height after heating to temperatures of .ltoreq.300.degree. C.
2. The clay of claim 1 characterized in that one or more metals selected from the group consisting of Group VIII metals, Group VI metals, Group 1B metals or mixtures thereof are incorporated into the clay.
3. The clay of claim 2 characterized in that the metals incorporated into the clay are one or more Group VIII metals.
4. The clay of claim 3 wherein the metals are selected from the group consisting of platinum, palladium and mixtures thereof.
5. The clay of claim 2 characterized in that the clay has a surface area of at least about 100 m.sup.2 /gm.
6. The clay of claim 5 characterized in that the clay has a pore volume of at least about 0.03 ml/gm.
7. The clay of claim 6 wherein the swellable clay is a smectite.
8. The smectite clay of claim 7 wherein the smectite is selected from the group consisting of montmorillonite, bentonite, beidellite, nontronite, saponite, hectorite and fluorohectorite.
9. The clay of claim 6 wherein the swellable clay is a mica.
10. The mica clay of claim 9 wherein the mica is selected from the group consisting of fluoromicas and synthetic taeniolite.
11. The clay of claim 6 characterized in that the pore volume ranges from about 0.03-0.10 ml/gm.
12. The clay of claim 5 characterized in that the surface area ranges from about 100-400 m.sup.2 /gm.
13. A process for preparing a stable pillared clay having a reduced gallery height of .gtoreq.4 and .ltoreq.7 Angstroms comprising reacting a swellable clay with a zirconium compound acting as a pillaring agent, water and surfactant for a period sufficient to form a zirconyl pillared clay, washing the resulting solid and calcining the washed solid.
14. The process of claim 13 characterized in that the surfactant has the general formula C.sub.11-15 H.sub.23-31 O CH.sub.2 CH.sub.2 O!.sub.x H.
15. The process of claim 14 characterized in that the molecular weight of the surfactant ranges from about 250 to 2000.