Graphene Oxide Membranes with Heterogeneous Nanodomains for Efficient CO₂ Separations

Achieving high membrane performance in terms of gas permeance and carbon dioxide selectivity is an important target in carbon capture. Aiming to manipulate the channel affinity towards CO₂ to implement efficient separations, gas separation membranes containing CO₂ -philic and non-CO₂ -philic nanodomains in the interlayer channels of graphene oxide (GO) were formed by intercalating poly(ethylene glycol) diamines (PEGDA). PEGDA reacts with epoxy groups on the GO surface, constructing CO₂ -philic nanodomains and rendering a high sorption capacity, whereas unreacted GO surfaces give non-CO₂ -philic nanodomains, rendering low-friction diffusion. Owing to the orderly stacking of nanochannels through cross-linking and the heterogeneous nanodomains with moderate CO₂ affinity, a GO-PEGDA500 membrane exhibits a high CO₂ permeance of 175.5 GPU and a CO₂ /CH₄ selectivity of 69.5, which is the highest performance reported for dry-state GO-stacking membranes.