Conductivity and chemical stability of SrCe0.92Nb0.03Tm0.05O3−δ membrane prepared by modified sol–gel method

SrCe0.92Nb0.03Tm0.05O3−δ powders were synthesized by a modified sol–gel method using citrate as a chelating agent. X-ray diffraction (XRD) analysis verified SrCe0.92Nb0.03Tm0.05O3−δ powders and membranes consisting of a single perovskite phase. The morphologies of the sintered membranes were investigated by using scanning electron microscopy (SEM) technique. Stability tests demonstrated that the Nb introduction into doped strontium cerate greatly enhanced the chemical stability. Electrical conductivities of SrCe0.92Nb0.03Tm0.05O3−δ and SrCe0.95Tm0.05O3−δ were measured by the four-point DC method under 10% H2/He atmosphere and temperatures (700–900 °C). With a maximum conductivity of 0.0067 S cm−1 at 900 °C, the total electrical conductivity of SrCe0.92Nb0.03Tm0.05O3−δ increases with increasing temperature. The H2 permeation flux of SrCe0.92Nb0.03Tm0.05O3−δ is 0.035 mL cm−2 min−1 when 40% H2/He and Ar were used respectively as the feed and sweeping gases at 900 °C.