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Hydrogen and ammonia are ubiquitous chemical raw materials with a wide range of industrial applications. Methane steam reforming and Haber-Bosch process are the most commonly used industrial technology for hydrogen...

Mixed protonic–electronic conducting (MPEC) ceramic membranes with high H2 permeability and stability are significant for practical H2 separation. CO2‐tolerant lanthanum tungstate oxides have received much attention, but their low H2 permeability is their main problem for membrane applications. Herein, an efficient in‐situ exsolution strategy is proposed to enhance the H2 permeability and CO2 stability of lanthanum tungstate‐type membranes. During H2 permeation, the catalytic Pd nanoparticles are in‐situ generated from the bulk oxide lattices and dispersed evenly on the membrane surfaces, which greatly promotes the H2 surface exchange kinetics. Also, the protonic conductivity of the membranes is effectively improved through the introduction of Pd. Consequently, the H2 permeation flux is increased by 3.5 times and a maximum H2 flux of 1.3 mL min−1 cm−2 is achieved at 1000 °C through the La5.5(W0.6Mo0.4)0.95Pd0.05O11.25‐δ (LWMPd) membrane. The LWMPd membrane shows outstanding long‐term chemical stability during 300 h continuous operation in a CO2‐containing atmosphere. Therefore, this in‐situ exsolution formation of Pd nanoparticles provides effective guidance for developing competitive MPEC membranes for H2 separation and purification.

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