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

Abstract

Sandwich-type membranes comprising of graphene oxide (GO) as a "bun" and sodalite (SOD) nanocrystals with different morphology and size as an inner layer were prepared. First, the SOD nanocrystals with spheroidal (size of 30 nm) and flake-like (size of 150 nm) morphology were synthesized from precursor suspensions containing the same amount of GO as a modifier but different amount of water. Second, the SOD nanocrystals with different morphology and size were deposited between two GO layers to form the sandwich-type membrane. The performance of the sandwich-type membranes in H2/CO2 gas separation was optimized by tuning the properties of the SOD inner layer. The membrane containing spheroidal SOD nanocrystals showed higher H2 permeance of 4003±1965 GPU and H2/CO2 selectivity of 45.5±1.7 at 25 ºC in comparison to the pristine GO membrane (1642±145 GPU and H2/CO2 selectivity of 11.2±2.1).