Zeolite covered polymer derived ceramic foams: novel hierarchical pore systems for sorption and catalysis

Abstract

Open cell polymer derived ceramic foams were prepared by a self-foaming process of a filler loaded poly(silsesquioxane) and subsequent pyrolysis at 1000°C in nitrogen atmosphere. A 1 : 1 mixture by weight of elemental Si and SiC was introduced as particulate filler. Foam samples without and with addition of a small amount (1.5 wt-%) of Cu₂O were prepared. Open cell ceramic foams with average cell diameter of 0.5–1.5 mm, compressive strength of up to 3 MPa and porosity of up to 90% were used as supports for direct crystallisation of MFI type zeolite under partial dissolution/recrystallisation of the ceramic foam. The partial transformation of the Si–O–C based foam material by hydrothermal crystallisation at 150°C for 0–96 h resulted in a well distributed zeolite coating with excellent adhesion on the foam surface. Characterisation of the zeolite/ceramic foam composites was carried out by XRD measurements in order to determine the amount of zeolite in the composite. ²⁹Si MAS NMR experiments were conducted to investigate the influence of Cu₂O addition on the crystallisation behaviour.

Keywords:

• CATALYSIS
• CERAMIC FOAMS
• MAGIC ANGLE SPINNING NMR
• NITROGEN ADSORPTION
• SUPPORTED CRYSTALLISATION
• ZEOLITE