Sandwich-type H2/CO2 membranes comprising of graphene oxide and sodalite crystals with adjustable morphology and size

Sandwich-type membranes comprising of graphene oxide (GO) as a “bun” and sodalite (SOD) nanocrystals with different morphologies and sizes as an inner layer were prepared. First, the SOD nanocrystals with spheroidal (size of 30 nm) and flake-like (size of 150 nm) morphologies were synthesized from precursor suspensions containing the same amount of GO as a modifier but different amounts of water. Second, the SOD nanocrystals with different morphologies and sizes were deposited between two GO layers to form the sandwich-type membrane. The performance of the sandwich-type membranes in H 2 /CO 2 gas separation was optimized by tuning the properties of the SOD inner layer. The membrane containing spheroidal SOD nanocrystals showed higher H 2 permeance of 4003 ± 1965 GPU and H 2 /CO 2 selectivity of 45.5 ± 1.7 at 25 °C in comparison to the pristine GO membrane (1642 ± 145 GPU and H 2 /CO 2 selectivity of 11.2 ± 2.1).