Interconnected Pore Channels with Sieving Windows Deliver Ultrafast Propylene Purification

Abstract

Abstract Molecular sieving is regarded as the most effective strategy for separating propylene from propane, yet it remains limited by the long-standing trade-off between adsorption capacity and diffusion kinetics. Here, we reveal exceptional propylene/propane separation performance in an aluminophosphate framework, AlPO-ERI, featuring interconnected pore channels with sieving windows that couple high propylene uptake with ultrafast molecular diffusion. Large erionite cavities interconnected by elliptical eight-membered ring windows enable high propylene uptake, with the windows selectively admitting propylene in an upright configuration that fits the window cross-section while sterically excluding propane. The multiple propylene-suitable windows provide parallel diffusion pathways for intercage transport, while the electrically neutral framework offers a smooth and weakly interacting in-cage environment, together facilitating the ultrafast diffusion of propylene within the pores. Gas-loaded SCXRD (AlPO-ERI⊃3C3H6) and simulation calculations clearly validate the recognition and diffusion mechanisms of the structure and propylene. Breakthrough experiments demonstrate a record propylene dynamic uptake of 53.7 cm3 g–1 among propylene/propane sieving adsorbents and a productivity of 43.9 L kg–1 for over 99.9% propylene at ambient conditions, with remarkable cyclic and humidity stability. Combined with its scalable synthesis and low cost, it shows potential for industrial applications.