Self-catalyzing thin BaCe0.5Fe0.5O3−δ hydrogen-permeation membranes on porous YSZ–Ni supports with high flux

Hydrogen (H2) separation membranes have attracted considerable interest in regard to H2 production industries, membrane reactors, and hydrogen isotope separation in fusion energy systems. BaCe0.5Fe0.5O3−δ (BCF), a mixed protonic and electronic conductor, is a promising candidate for hydrogen permeation. However, conventional dense BCF membranes require thickness >0.3 mm to ensure mechanical integrity, resulting in long proton transport distances and limited permeation flux. In this study, we developed a thin BCF membrane supported on a porous yttria-stabilized zirconia–nickel (YSZ–Ni) substrate to overcome these limitations. A dense BCF layer with a thickness of approximately 8 µm was co-sintered with a YSZ–NiO support and then subsequently reduced to form a porous YSZ–Ni substrate, providing mechanical support and facilitating gas diffusion. Owing to excellent sintering compatibility between BCF and YSZ–NiO, a crack-free dense membrane was achieved. Hydrogen permeation tests between 500 and 700 °C showed a substantial flux enhancement compared to thick BCF membranes. At 700 °C and 40% H2 feeding, the BCF||YSZ–Ni membrane reached 2.26 × 10−2 mol m−2 s−1, nearly five times higher than that of a dense BCF pellet under identical conditions. Electrochemical impedance spectroscopy further revealed that BCF exhibits sufficient catalytic activity for hydrogen surface reactions, eliminating the need for an additional catalyst layer. These results demonstrate that YSZ–Ni porous-supported thin BCF membranes offer an effective and scalable strategy for improving hydrogen permeation performance in ceramic-based separation systems.