Preparation and characterization of highly CO₂ permeable and selective graphene oxide membranes by introducing gutter layers into porous substrates

Here, we present graphene oxide (GO)-based thin-film composite (TFC) membranes with enhanced CO₂ separation performance using a surface-modified substrate for uniform GO depositions. We extensively characterized the surface properties of porous substrates to identify optimal conditions for universal and uniform GO selective layer. Our results reveal that incorporating polyvinylpyrrolidone (PVP) as a gutter layer is essential for achieving consistent and regular GO layer coating. As a result, the developed GO membranes demonstrate a CO₂ permeance of 350 GPU, which is a ∼350 % improvement over the GO membranes without gutter layer, coupled with a higher selectivity for CO₂/N₂ and CO₂/CH₄ pairs. The results indicate the excellent potential for significantly enhanced CO₂ separation performances with the development of suitable support membranes.