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.