Facile synthesis of porphyrin-based PAF membrane for hydrogen purification

This work utilizes interfacial polymerization to synthesize continuous PAF membrane. Here, a pore structure suitable for hydrogen separation was constructed by introducing rigid porphyrin groups, and the PAF membrane exhibited excellent hydrogen purification ability. [Display omitted] •Interfacial polymerization, a facile method for synthesis of continuous PAF membrane.•Rigid porphyrin-based block, enhancing the rigidity of the membrane structure.•Pore size smaller than 1 nm, suitable for molecular sieve separation of H2. Available online Hydrogen (H2) is a promising clean energy source and its separation and purification from fossil fuels and natural gas is of great significance. Microporous continuous membrane separation is an efficient and energy-saving separation method, in which membranes with a pore size less than 1 nm can better achieve size-dependent sieving of H2. Porous aromatic framework (PAF) continuous membranes are expected to exhibit high-efficiency gas separation due to their highly connected channels as well as structural stability and channel design. Synthesis of continuous PAF membranes using facile methods remains a challenge. Here, we synthesized ultrathin continuous porphyrin-based PAF (ppPAF) membrane using an interfacial polymerization approach. The design introduced rigid porphyrin groups, resulting in a pore size of 0.7 nm for the ppPAF membrane. The ppPAF membrane showed a H2 permeance of 709.2 gas permeation units (GPU), with a H2/CO2 selectivity of 78.8. The ppPAF membrane showed a H2/CH4 selectivity of 93.3, with a H2 permeance of 624.8GPU. Our results provide new ideas for the synthesis of continuous PAF films.