Tailored for hydrogen separation in the temperature window of the water–gas shift reactions: A metal-polymer dual-phase membrane with mixed proton-electron conduction

Efficient hydrogen separation at intermediate temperatures is important for membrane-assisted water–gas shift and reforming processes. Herein, a metal–polymer dual-phase mixed proton–electron conducting membrane was developed by capillary infiltration of OPBI into a porous titanium support, followed by phosphoric acid doping. In this structure, the Ti framework provides a continuous electron-conducting pathway, while PA-doped OPBI forms a dense proton-conducting phase. Pt layers promote H 2 dissociation and recombination, enabling selective hydrogen transport through coupled proton–electron conduction. The optimized Ti-PA/OPBI-Pt membrane, which has a thickness of 0.5 mm and a Ti pore size of 10 μm, achieved an H 2 flux of 0.96 mL min −1 ·cm −2 at 300 °C under a 50% H 2 /N 2 feed, with 100% H 2 /N 2 selectivity. Arrhenius analysis indicated different rate-controlling regimes below and above 200 °C. The membrane also maintained a stable H 2 flux of ∼0.63 mL min −1 ·cm −2 for over 200 h at 220 °C. This work provides a feasible metal–polymer mixed-conducting membrane strategy for hydrogen separation in the water–gas shift temperature window.