Galvanic hydrogen pumping in the protonic ceramic perovskite BaCe0.2Zr0.7Y0.1O3−δ

A series of experiments were performed on tubular BaCe0.2Zr0.7Y0.1O3−δ (BCZY27) protonic ceramic hydrogen diffusion membranes in which hydrogen flux was obtained using a tube-in-shell test apparatus with a 22-cm2 membrane active area and hermetic glass seals. This was accomplished by measuring permeate composition using a mass spectrometer and bubble-meter measurement of outlet flow rates over a broad range of current densities and furnace temperatures. A maximum current efficiency of 98.6% was achieved at 775 °C at 800 mA cm−2, producing over 6 nmL cm−2 min−1 of hydrogen at virtually 100% selectivity. The data generated through these experiments has been valuable in the evaluation of fabrication methods and hermetic sealing techniques required for large area membranes that are suitable for commercialization. Applications include hydrogen separation, ammonia synthesis and gas-to-liquids fuel processing via methane dehydrogenation. Additionally, the experiments provided valuable insight into the charge-transport processes in BCZY27 membranes where multiple charge carrier species are involved.