New perovskite membrane with improved sintering and self-reconstructed surface for efficient hydrogen permeation

Perovskite oxide membranes have attracted increasing attentions for hydrogen purification recently, which separate hydrogen based on the ionic diffusion mechanism and have the advantages of cost effectiveness and capability for coupled reaction. However, such membranes usually show much lower hydrogen permeation flux than Pd membrane due to either low proton or/and electron conductivity of the oxide bulk or poor surface reaction kinetics for hydrogen activation. Herein, we report a durable perovskite-based hydrogen permeation membrane that tackles both the problem of poor bulk proton/electron conductivity and surface reaction kinetics of conventional perovskite membranes, which is developed based on an exsolution-induced self-surface reconstruction strategy. More specifically, a Ba(Ce_0.7Zr_0.1Y_0.1Yb_0.1)_0.95Ni_0.05O_3-δ (BCZYYbNi) perovskite is synthesized. During operation, Ni is exsolved from the perovskite oxide lattice to decorate the membrane surface and grain boundary, thus promoting hydrogen adsorption/dissociation at membrane surface and providing external shorted circuit for electron transport. As a result, a 0.45 mm thick BCZYYbNi membrane exhibits record H₂ permeation flux of 0.42 mL min⁻¹ cm⁻² [STP] at 800 °C under 10% H₂–N₂/Ar gradient. As well, the membrane demonstrates stable H₂ permeability during a test period of 200 h, thus providing a new way for developing cost-effective hydrogen separation membrane.