A contribution to the development and characterization of pillared layered structures

Pillared Interlayered Clays (PILCs) are an interesting class of porous materials. Due to their high surface area and permanent porosity they are very attractive solids for adsorption and catalysis purposes. This PhD-thesis brings a contribution to the development of pillared layered structures (PLS), based on several clay substrates and applying new synthesis methods. The research is focused on the characterization of the adsorbents using many different techniques. Also the suitability of the obtained materials for the application as gas adsorbent and chemical sensor is investigated.; The Al-pillaring of laponite and hectorite has been performed, together with a theoretical study of their porosities allowing an evaluation of the potentials and limitations of these materials as adsorbent.; By a new preparation method, called 'self-assembly', homogeneous multilayer films of Al-pillared clay have been grown on a Au-support by means of the alternate adsorption of oppositely charged species. The interesting application of the Al-pillared clay film as chemically sensitive sensor is shown.; Beside aluminium, also the Zr-intercalation on clays is investigated, resulting in highly porous materials with large specific surface areas. By a new synthesis method, including the pre-adsorption of amine templates in the clay interlayer region, a further enhancement in surface area and micropore volume can be established. The obtained PILCs are tested for their gas adsorption behaviour by recording gas adsorption isotherms.; Finally, a new type of mesoporous molecular sieve has been developed, exhibiting interesting potential applications with respect to the adsorption of large macromolecular species for acid-catalyzed processes. This new material is called the 'Porous Clay Heterostructure' (PCH), resembling, the pillared clay in which dense silica particles constitute the pillars. During the synthesis, surfactants play a structure-directing role allowing a tuning of the porosity. It is proven that by a simple preparation procedure, within a short reaction time and at ambient temperature, very high surface areas and pore volumes on clays can be obtained.