Novel alumina ‘KK Leaf Structures’ as catalyst supports

A method has been devised in which alumina can be formed into a layer of thin leaf-like structures that have a thickness of 0.2–0.8 μm. This consists of a process in which aluminium iso-propoxide is transformed into a sol–gel and then: frozen (−195 °C), freeze-dried (−60 °C), and finally calcined (450 °C). These special conditions lead to the formation of a structure that is named: ‘KK Leaves’.

After calcining at 450 °C, the leaves have a specific surface area of 282 m²/g, an average pore size of 2.8 nm, and exhibit a curly shape. The structure has the appearance of a loosely packed (but ordered) collection of thin curly leaves with fine ribs resembling leaf veins on trees and plants. They would readily act as a support, e.g., for a catalyst, or adsorbents, or act as a membrane filter.