Stable, asymmetric, tubular oxygen transport membranes of (Sc₂O₃)_0.10(Y₂O₃)_0.01(ZrO₂)_0.89 – LaCr_0.85Cu_0.10Ni_0.05O_3-δ

Oxygen transport membranes have the potential to deliver pure and cheap oxygen to chemical reactors, combustors, gasifiers etc., given that geometry, microstructure and material properties are optimized. This work demonstrates the first successful preparation of dual-phase tubular, asymmetric oxygen transport membranes consisting of a new electronic conductor LaCr_0.85Cu_0.10Ni_0.05O_3-δ mixed with (Sc₂O₃)_0.10(Y₂O₃)_0.01(ZrO₂)_0.89 as ionic conductor. Challenges related to Cr-volatility were overcome by using Fe₂O₃ as a sintering aid. The sintering aid decreased mismatches in shrinkage and thermal expansion between the four layers in the asymmetric membrane and decreased the sintering temperature such that the Cr-volatility was suppressed. The membranes reached an oxygen flux of 0.28 ml∙min⁻¹∙cm⁻² in an air/N₂ atmosphere at 950 °C. Furthermore, the membranes showed a stable oxygen flux after exposure to different atmospheres, including air/CO₂ and air/H₂ gradients. The successful fabrication of stable, asymmetric, tubular membranes opens the possibility for future integration in syngas or oxy-combustion applications.