Efficient separation of propane and propylene by nanocrystals of a metal–organic framework-based splitter

The separation of propane/propylene mixtures to produce polymer-grade propylene represents an important yet challenging task in the petrochemical industry. Metal-organic frameworks (MOFs) hold particular promise for the energy-efficient adsorptive separation of propane/propylene, in light of their structural diversity as well as highly tunable pore dimensions. MOFs exhibiting selective molecular exclusion for propylene over propane render exceptionally high adsorption selectivity. However, the relatively low adsorption capacity and/or slow diffusion kinetics have largely limited their separation efficiency. Here we report the fabrication of nano-sized crystals of a MOF-based splitter for propane and propylene. Compared to the micro-sized MOF samples, the nanocrystals display enhanced adsorption kinetics as well as notably improved adsorption capacity, making a new record with the highest efficiency for the separation of propane/propylene among all reported MOF-based splitters. Our study may shed light on the development of MOF-based adsorbents with optimal efficiency for industrially challenging gas separations.