Sub-micro porous thin polymer membranes for discriminating H₂ and CO₂

Polymeric membranes with high permeance and remarkable selectivity for simultaneous H-2 purification and CO2 capture under industry-relevant conditions are absent. Herein, sub-micro pores with precise molecular sieving capability are created in ultra-thin (13-30 nm) polymer membranes via controllable transformation of amine-linked polymer (ALP) films into benzimidazole-and-amine-linked polymer (BIALP) layers. The BIALP membranes exhibit stable unprecedented H-2/CO2 selectivity of 120 with a H-2 permeance of 315 GPU. Furthermore, high pressure (up to 11 bar) and thermal (up to 300 degrees C) resistance is delivered. This work provides a concept on designing porous polymeric membranes for precise molecular discrimination.