Facile In Situ Hydrothermal Synthesis of Layered Zirconium Phenylphosphonate Molecular Sieve Membranes with Optimized Microstructure and Superb H₂/CO₂ Selectivity

Layered molecular sieve membranes containing uniform interlayer galleries have offered unprecedented opportunities to reach a performance far beyond the Robeson upper bound line. In this study, we took the initiative to prepare layered zirconium phenylphosphonate (ZrPP) molecular sieve membranes with optimized microstructure on tetragonal zirconia (t-ZrO₂) buffer layer-modified porous α-Al₂O₃ substrates by facile in situ hydrothermal growth. Relying on the 3.2 Å-sized gallery height and preferential CO₂ adsorption behavior, prepared ZrPP membranes showed exceptional H₂/CO₂ selectivity (>100) as well as considerable H₂ permeability. Furthermore, extraordinary thermal, mechanical, and chemical stability of ZrPP membranes made them potentially attractive for long-term operations under harsh conditions.