Performance of GO laminated membranes in H2/CO2 separation as a function of the membrane thickness

Hydrogen gas (H 2 ) is a promising energy carrier capable of replacing fossil fuels and achieving net zero emissions. However, purifying H 2 for applications like fuel cells and industrial processes is challenging due to impurities affecting performance. Two-dimensional (2D) materials, particularly graphene-based membranes, are promising for H 2 purification due to their unique properties. The hydrogen (H 2 ) permeation capability of graphene-based membranes is particularly significant. This study examines the use of commercial and cost-effective graphene oxide (GO) to fabricate multilayer graphene membranes, focusing on the impact of membrane thickness on H 2 and CO 2 separation. By using a scalable vacuum filtration method to coat porous ceramic substrates , membranes with controlled thicknesses were produced and characterised using AFM , FESEM , XRD , and gas permeation measurements. The study identified an optimal membrane thickness range (4 nm–250 nm) and the GO quantity (0.44 μg/cm 2 to 1.76 μg/cm 2 ) needed for effective H 2 /CO 2 separation. This research aims to guide the development of cost-effective, mass-produced 2D-based membranes for industrial H 2 purification. • 2D materials and graphene-based membranes are notable for their H 2 permeability. • GO membrane thickness 4–250 nm and quantity 0.44–1.76 μg/cm 2 for H 2 /CO 2 separation. • Permeance and selectivity as a function of the thickness of GO membranes. • Average commercial GO and scalable methods: potential high-permeability membranes. • Industrial requirements of high permeability and scalability: graphene's potential.