A robust metal–organic framework for simultaneous C2H4/C3H6 capture and C2H2/CO2 separation

Simultaneously capturing and separating high-purity C2H4 and C3H6 from cracked gas mixtures presents a significant challenge. Herein, a robust metal–organic framework (Cu(BF4)2(4-DPDS)2) was designed featuring a gourd-shaped one-dimensional channel. Its specific alkenes match structure can only adsorb alkenes while completely excluding alkanes. With a remarkable adsorption selectivity of 76,203 for equimolar C2H4/C2H6 and high selectivity of 159 for equimolar C3H6/C3H8, Cu(BF4)2(4-DPDS)2 not only achieves >99 % purity separation of C2H4 and C3H6 from binary mixtures but also simultaneously captures and separates these compounds from seven-component cracking gases at ambient conditions. Its performance stability remains intact even under 75 % RH conditions, thanks to its robust framework. Based on the particular gourd-shaped channel, it can also achieve efficient C2H2/CO2 separation. Ab initio Molecular Dynamics simulations demonstrate the dynamic diffusion process of gas molecules in the structure, and in situ infrared analyses reveal the framework's rich C-H•••F and S•••π binding sites with C2H4 and C3H6. This material's robust structure, exceptional alkene sieving capabilities, and repeatable separation performance comprehensively showcase Cu(BF4)2(4-DPDS)2 as a unique metal–organic framework for simultaneous recognition and capture of C2H4 and C3H6.