(4d) Hydrogen Selective Membranes by Assembly of Anisotropic Nanoparticles

At least 80% reduction of CO2 emissions from IGCC coal-fuelled power plants can be accomplished by incorporating a WGS membrane reactor technology, resulting in residual carbon dioxide emissions of 0.1 KgCO2/kWhr. A scalable membrane fabrication technique that can reliably produce thousands square meters of hydrogen selective membrane is therefore desirable.

Results from a simple novel method for the fabrication of H2-selective silica membranes will be presented. The method represents a drastic departure from the other approaches and relies on the use of layered building blocks (tiles) that have very small pores and are expected to be H2-selective in the direction perpendicular to the tile surface. The tiles have well-defined ?crystalline? structures consisting of a majority of interconnected SiO4 tetrahedra and a relatively small number of terminal Si-OH surface groups. Our objective is to use the silicate tiles as building blocks for the formation of extremely thin, H2-selective, highly ordered SiO2 coatings.

We have synthesized molecular sieve particles with plate like morphology and large aspect ratio and developed swelling and delamination procedures that lead to improved aspect ratio and dispersability in solvents. We also demonstrated deposition processes that lead to uniform, high-coverage (~100%) coatings of molecular sieve particles on porous supports and obtained membranes with hydrogen selectivity significantly above the one explained by Knudsen diffusion.

Acknowledgement: Funding is provided by DOE, Project Number DE-FG26-04NT42119 and IREE.