Oxygen permeation in La0.6Sr0.4Fe0.9Ga0.1O3-δ dense membrane:: effects of surface microstructure

The use of perovskite mixed ionic-electronic conducting membranes for industrial applications, such as oxygen dissociation from air and methane conversion into syngas, requires high oxygen permeation fluxes. In this regard, the improvement of the permeation rates through a La0.6Sr0.4Fe0.9Ga0.1O3-delta (LSFG) membrane was performed by modifying the surface by controlling the average grain size of the perovskite material or by coating its surface with a thin layer of La0.6Sr0.4Co0.8Fe0.2O3-delta. In both cases, the permeation-limiting regime was determined and the oxygen surface coefficient k(s) and diffusion coefficient D-v were evaluated. The low value of k(s) was found to be the most critical parameter for the performance of these LSFG membranes.