Weijian Sun, Kaicheng Yang, Yifan Zhao, Liping Sun, Qingchi Xu, Jian Weng, Jun Xu
Traditional petroleum distillation faces high energy demands, necessitating innovative alternatives like membrane separation. This study presents a breakthrough in dual-range and precise pore size modulation of metal-organic frameworks (MOFs) through a ligand functionalization strategy. By tailoring steric configurations and spatial orientations of light-responsive azobenzene groups, we achieved broad-range pore tuning (0.41 to 0.68 nanometers) via functional group length variation, coupled with subnanometer precision through reversible trans-to-cis photoisomerization. Four representative branched alkanes were selected to validate the MOF’s high selectivity. Results showed its capacity to generate a constant carbon-atom-count–dependent permeation gradient, realizing a four-step sequential separation that increased C 6 H 14 purity from 25 to 92.2%. This synergistic approach uniquely combines large-scale pore adjustment with dynamic fine-tuning, decoupling separation efficiency from energy-intensive processes. The membranes’ structural stability and reversible light responsiveness further highlight their potential for sustainable hydrocarbon processing. By integrating molecular design with stimuli-responsive control, this work advances MOF-based membranes as a transformative solution for energy-efficient petroleum fractionation and precise molecular sieving.