(149f) Steam Stability of Layered Zeolites Suitable for Hydrogen Transport

In this study, we demonstrate potential of zeolite nanosheets with 6-member ring (6MR) apertures for preparation of hydrogen permselective membranes. The preparation technique is based on exfoliation of layered zeolites into their constituent nanosheets, formation of closely packed monolayers on porous substrates, and then performing secondary growth. Steam stability of these zeolites in conditions relevant to steam methane reforming and water gas shift reactions over a period of about 3 months using X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), multinuclear solid state NMR, and Ar adsorption analyses was investigated. It was found that zeolites with lower concentrations of structural defects perform better in steam. In line with this observation, enhanced steam stability of the zeolites treated with silicon tetrachloride ( SiCl₄ ) was seen. This work highlights the importance of zeolite synthesis or post-synthesis methods suitable to eliminate structural defects for applications where high temperature steam is present.