A Hydrogen‐Permselective Silicon Oxycarbide Membrane Derived from Polydimethylsilane

A novel microporous membrane has been prepared by modifying an asymmetric SiC support using polydimethylsilane (PMS). One membrane, pyrolyzed at 573 K, possesses H 2 /N 2 selectivity of ∼100 and H 2 permeance of 8.9 × 10 −8 mol·m −2 ·s −1 ·Pa −1 at 473 K. The other membrane, pyrolyzed at 873 K, has a lower H 2 /N 2 selectivity of ∼40 and lower H 2 permeance of 4.9 × 10 −9 mol·m −2 ·s −1 ·Pa −1 at 473 K. Permeation in both membranes exhibits the characteristics of activated diffusion at elevated temperatures. A higher pyrolysis temperature results in a less‐permeable membrane. The support preparation and the thermal events of PMS are analyzed. The effects of pyrolysis temperature on membrane property are discussed.