| 摘要: | 由於鍶鈰氧化物具有高的質子與電子導電率與低的活化能，因此可應用於氫氣傳輸透膜 (HTM)之材料。HTM對氫氣具有通透性，可用於分離純化煤碳、石灰石等石化燃料氣體中之氫氣。因此HTM材料必需對環境中的一氧化碳、二氧化碳及硫化物需具有良好的化學穩定性，並且由適當的微結構設計以提供足夠的機械強度。本研究利用固相反應法來製備SrCe1-xZrxO3?δ (x=0, 0.1, 0.2, 0.3, 0.4, 0.5)質子導體氧化物，探討鋯含量的添加對其燒結行為、化學穩定性與導電性影響之研究。X光繞射儀、掃描式電子顯微鏡來鑑定晶體結構、觀察表面形貌。隨著Zr摻雜含量增加，破斷面由封閉性孔洞轉變成開放性孔洞，燒結不緻密，孔隙率增加。SrCe0.6Zr0.4O3-δ (SCZ0.4)呈現多孔結構，於1500℃燒結4小時，具有最低收縮率5.98%、最大吸水率7.09%與最大孔隙率26.80%。由對CO2化學穩定性的實驗分析得知，隨著Zr摻雜含量增加，SrCe1-xZrxO3-δ (0≦x≦0.5)中之CeO2與SrCO3兩相峰值相對強度降低，Zr摻雜含量為SrCe0.8Zr0.2O3-δ (SCZ0.2)以上，穩定性即可獲得改善。另外由導電率分析顯示，SrCe1-xZrxO3-δ (0≦x≦0.5)系統之導電率隨著Zr摻雜含量的增加而降低。SCZ0.4多孔結構在HTM支撐層材料應用上具有相當的潛力。
Strontium cerium oxide can be applicated on hydrogen transport membranes (HTM) beacuse of their relativity high proton and electrical conductivities and lower activations energy. HTM have a permeability to hydrogen, using for separating and purifing hydrogen from coal and limestone of fossil fuels. Therefore, the good chemical stability in the enviroment of corbon monoxide, corbon dioxide and sulfides, and to provide suitable mechanical strength by apropriating microstrctures design. In this study, SrCe1-xZrxO3?δ (x=0, 0.1, 0.2, 0.3, 0.4, 0.5) proton-conducting oxides have been prepared using a solid state reaction method. The relationship between the Zr doping content and microstructure, sinterability, chemical ability and conductivity of these SrCe1-xZrxO3?δ (0.0≦x≦0.5) proton-conducting oxides. SrCe1-xZrxO3?δ (0.0≦x≦0.5) are studied systematically by using X-ray Diffraction for the microstructure identification, by Scanning Electron Microscopy for surface mohpology observation. The results of SEM observation on the morphology of fracture surface reveals the porosity of sintered oxides increases with increasing the Zr doping content. Since the Zr doping content would decrease the siterability, the closed pores tranferring into open pores can be seen on the fracture surface. In addition, the results of thermo dilatometer analysis present a shrinkage of 5.98% and water absorption of 7.09% and porosity of 26.80 % occured at the composition of SrCe0.6Zr0.4O3-δ (SCZ0.4) sintered at 1500℃for 4 hurs, respectively. The results of CO2 enviroment test reveals that the relative intensity of CeO2 and SrCO3 phases decreases with increasing the Zr content. This evidences that the chemical stability of SrCe0.8Zr0.2O3-δ (SCZ0.2) would improved by increasing Zr content. However th condutivity of SrCe1-xZrxO3?δ (0.0≦x≦0.5) oxides decreases with increasing the Zr doping content. As a result, SCZ0.4 is suggested to be a potential support layer material for HTM applications. |
