**3. Characterization of zeolite powders and membranes**

The crystalline structure of the as-synthesized zeolites and membranes was determined by XRD patterns. XRD was carried out on a Philips 1710 diffractometer using CuKα radiation (α =1.541° A). The characteristic vibration bands for zeolite powders were investigated by FTIR (Nicolet 5PC, Nicolet analytical instrument, Madison, WI). Thermogravimetric analyses (TGA) and differential thermal analyses (DTA) were performed in static air using the thermogravimetric analyzer (NETZSCH STA 409 C F3 Jupiter, Germany). The samples were heated at a rate of 10°C min<sup>−</sup><sup>1</sup> under air flow. The N2 adsorption/desorption measurements of different zeolite powder were evaluated on a volumetric gas adsorption analyzer (autosorb-iQ-MP, Quantachrome) at 77 K. The sample used in the adsorption measurement was degassed at 423 K for 6 h before the measurements. Pore size distributions and surface area data of the synthesized powders were collected from N2 adsorption at 77 K. The same apparatus was also used for the measurement of H2 adsorption/desorption isotherms at 77 K up to 1 bar. Prior to adsorption study, the sample was out-gassed appropriately at 250°C for 24 h under high vacuum (106 mbar). In this case, He (99.999%) and N2 (99.999%) were used as carrier gas. Accessible microporous volume has been estimated by using the Dubinin-Radushkevich (DR) method. Transmission electron microscopy (TEM) measurements were carried out with a Tecnai G2 30ST (FEI) operating at 300 kV. The microstructure, elemental mapping with EDAX, and cross-sectional line scanning of the synthesized membranes were examined using field emission scanning electron microscopy (FESEM: model Leo, S430i, UK). X-ray photoelectron spectroscopy (XPS) measurements of support, chemically modified support, and respective membrane were carried out on an XPS system (PHI 5000 VersaProbe II, ULVAC-PHI, INC., USA) using a monochromatic Al Kα X-ray source (1486.6 eV). To identify the bonding between seed crystal and support surface, Raman analysis was carried by Raman microscope (RENISHAW inVia, UK).

The gas permeation experiment was done by a specially designed permeation cell where the membrane was mounted in a stainless steel permeation cell and

sealed by silicone O-rings. Prior to permeation experiment, the leak test was carried out in order to obtain the correct data. The complete description of gas permeation measurement is given in the supporting information of our published paper [40].
