Hydrogen separation through tailored dual phase membranes with nominal composition BaCe_0.8Eu_0.2O_3-δ:Ce_0.8Y_0.2O_2-δ at...

Hydrogen permeation membranes are a key element in improving the energy conversion efficiency and decreasing the greenhouse gas emissions from energy generation. The scientific community faces the challenge of identifying and optimizing stable and effective ceramic materials for H₂ separation membranes at elevated temperature (400-800 °C) for industrial separations and intensified catalytic reactors. As such, composite materials with nominal composition BaCe_0.8Eu_0.2O_3-δ:Ce_0.8Y_0.2O_2-δ revealed unprecedented H₂ permeation levels of 0.4 to 0.61 mL·min^-1·cm^-2 at 700 °C measured on 500 μm-thick-specimen. A detailed structural and phase study revealed single phase perovskite and fluorite starting materials synthesized via the conventional ceramic route. Strong tendency of Eu to migrate from the perovskite to the fluorite phase was observed at sintering temperature, leading to significant Eu depletion of the proton conducing BaCe_0.8Eu_0.2O_3-δ phase. Composite microstructure was examined prior and after a variety of functional tests, including electrical conductivity, H₂-permeation and stability in CO₂ containing atmospheres at elevated temperatures, revealing stable material without morphological and structural changes, with segregation-free interfaces and no further diffusive effects between the constituting phases. In this context, dual phase material based on BaCe_0.8Eu_0.2O_3-δ:Ce_0.8Y_0.2O_2-δ represents a very promising candidate for H₂ separating membrane in energy- and environmentally-related applications.