Gas permeation property of silicon carbide membrane prepared using radiation curing of polymer precursor film

Takeyama, Akinori; Sugimoto, Masaki; Yoshikawa, Masahito

There is growing interest in H production using inorganic membrane stable in reactant gases such as carbon monoxide (CO) or steam. In this study, we prepared an inorganic membrane from polymer-derived silicon carbide (SiC) using electron beam curing of polymer precursor film. Alpha almina tube, which is chemically stable but has sized pore (averaged diameter size 100 nm), was used as the support. First, supports were dipped in the 10 mass% polycarbosilne (PCS), polymer precursor solution for 1 s and drawn up (the first dipping). After drying, some of those supports coated with PCS film were immersed into another PCS solution whose concentration was 3 mass% for 0.8, 1.5 and 2 s (the second dipping). They were cured by electron beam irradiation in helium atmosphere and pylolyzed at 973 K in argon atmosphere. H permeance of SiC membrane prepared via only the first dipping increased with increasing the temperature, but not following the Arrhenius plot. This means sub-nano meter sized pores and a few of large defects coexisted in the membrane. Whereas, H permeance of the membrane prepared via the first and 1.5s of second dipping increased following the Arrhenius plot. Activation energy of 7.5 kJ/mol calculated from slope of the plot indicates that pores of the support were plugged by SiC film and thermally activated H molecules diffused through the membrane by molecular sieving mechanism.