ZIRCONIA-PILLARED TETRASILICIC FLUOROMICA

Zirconia-pillared tetrasilicic fluoromicas are prepared from sodium tetrasilicic mica, Na-[Mg2.5Si4O10F2], using a commercial zirconyl acetate solution as the source of the zirconium polyoxocation pillars. Reproducible results are conveniently obtained without any preliminary heating of the pillaring solution, and the pillaring reaction is performed at ambient temperature. The resulting zirconia-pillared mica has a consistently higher crystallinity and layer spacing than pillared clays prepared from zirconyl chloride solutions and shows significantly higher thermal stability, an important factor in potential catalytic applications. Zirconia-pillared tetrasilicic fluoromica is a microporous material containing two-dimensional galleries with a height of 11 angstrom. The surface area is high, about 300 m2/g. After treatment in steam at 760-degrees-C for 17 h, the surface area is reduced only to approximately 200 m2/g. Thus, very small particles of ZrO2 dispersed between 10-angstrom-thick mica layers have been stabilized.