Cooperative control of intralayer and interlayer space in MOFs enables selective capture of intermediate-sized molecules

Adsorptive separation of the smallest or largest molecules from a mixture can be realized by the sieving effect; however, it is still an arduous task to specifically discriminate between the intermediate-sized component from a complicated multicomponent mixture. Here, we report a strategy via cooperative control of intralayer and interlayer space for selective adsorption of ethane from methane and propane on a 2D-layered MOF termed Ni(4-DPDS)2CrO4. The intralayer channels work as main adsorption sites, while interlayer channels are designed to achieve optimal discrepancy of kinetic diffusion rates. The restricted diffusion of C3H8 in the interlayer channels results in a dramatic inversed, equilibrium-kinetic, combined selectivity for C2H6/C3H8. Mixture breakthrough experiments manifest an efficient capture of C2H6 owing to the equilibrium-kinetic synergetic effect. The mechanism for selective gas adsorption is well supported by kinetic results and crystallography studies, demonstrating that fabrication of MOFs with multiple distinct controllable micropores enables selective capture of intermediate-sized molecules.