Oxygen permeability of LaGaO3-based ceramic membranes

Acceptor-type doping of perovskite-type La1−xSrxGa0.80−yMgyM0.20O3−δ (x=0–0.20, y=0.15–0.20, M=Fe, Co, Ni) leads to significant enhancement of the oxygen permeability due to increasing oxygen vacancy concentration and, thus, ionic conductivity. The increase in strontium and magnesium content is accompanied, however, with increasing role of the surface exchange kinetics as a permeation-limiting factor. At temperatures below 1223 K, the oxygen permeation (OP) fluxes through dense La(Sr)Ga(Mg,M)O3−δ membranes with the thickness less than 1.5 mm are mainly limited by the exchange rate at membrane/gas boundaries. For transition metal-containing La(Sr)Ga(Mg)O3−δ (LSGM) ceramics, the oxygen transport increases in the sequence Co