| Summary: | 碩士 === 國立中央大學 === 機械工程研究所 === 100 === Strontium-cerium oxides are beneficial for solid oxide hydrogen transport membranes (SOHTMs) because of their relatively high electrical and protonic conductivities. SOHTMs for the purpose of extraction of hydrogen from supplied gas mixtures are required to be: high selectivity for hydrogen but not others; mechanically strong enough to resist differential pressures across them; chemically stable under high partial pressure of moisture, carbon dioxide and sulfides; In this study, yttrium substituted strontium cerate (SrCe1-xYxO3-δ, x=0, 0.05, 0.1) was prepared by Citrate-EDTA complexing method. The microstructures were identified using X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM) and transmission electron microscope (TEM). Electrical conductivity was measured by two-point probe and chemical stability was examined under CO2 atmosphere. Preliminary results from XRD showed no detectable impurity phases when powders were calcined at 1000℃. The electrical conductivity increased as concentration of doped Y increased. However, At lower temperature (<700°C), the protonic conductivity dominated the total conductivity. At high temperature (>700°C), the electronic conductivity dominated the total conductivity. The chemical stability under CO2 was significantly to lose as more Y was doped into strontium cerates.
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