Ionic liquid composite graphene based on interlayer confinement effect for high efficiency CO₂/H₂ separation

The development of gas adsorbents suitable for high-temperature and low-pressure conditions is crucial for improving the efficiency and recovery rate of hydrogen purification. This study employs Density Functional Theory and Grand Canonical Monte Carlo simulations to calculate the interlayer spacing of 12 ionic liquid composite graphene (G-ILs) and analyze their CO₂/H₂ adsorption performance. Under a pressure of 0.4 bar, the CO₂ uptake of [DETA][PF₆] composite graphene reached as high as 7.95 mmol/g, which represents a 1163% increase compared to the CO₂ uptake of single-layer graphene. G-[EDA][BF₄] composite graphene exhibits the highest hydrogen purification efficiency. At 298 K and 1 bar, the CO₂/H₂ selectivity of [EDA][BF₄] composite graphene for the equimolar mixed gas reached as high as 1771. This study provides new insights into the development of novel adsorbents for hydrogen purification.