Hierarchical PBI membranes: Integrating porosity and compact layers suited for medium-temperature H2 separation in water-gas shift process

The development of membranes capable of directly separating H 2 by harnessing the residual heat from the water-gas shift reaction represents a significant challenge in the field of membrane separation technology. In this study, an asymmetric preparation strategy was employed to construct porous membranes with ultra-thin dense layers for achieving high-efficiency H 2 separation. We developed a novel ultra-thin polymer-based dual-phase hydrogen separation membrane with a porous architecture (p-OPBI-PANI), designed for operation under elevated temperatures ranging from 120 to 300 °C. This membrane achieved an exceptionally thin dense layer of 200 nm through a non-solvent-induced phase separation (NIPS) process utilizing dibutyl phthalate (DBP), while polyaniline (PANI) nanofillers were strategically incorporated into the polybenzimidazole (PBI) matrix to enhance structural and functional properties. Systematic modulation of non-solvent and nanofiller concentrations enables precise optimization of membrane morphology and separation performance. The optimized membrane demonstrates remarkable H 2 permeance (120 GPU) coupled with exceptional H 2 /N 2 selectivity of 205, surpassing conventional polymeric membranes. Furthermore, it exhibits robust operational stability in complex gas environments containing sulfur compounds (e.g., H 2 S) and high humidity, maintaining consistent performance over prolonged operation (>100 h). This work introduces a versatile fabrication paradigm for asymmetric-polymer hydrogen separation membranes, offering significant potential for hydrogen purification in industrial applications under harsh operating conditions.