本論文依照化學合成法中的共同沉澱法製備含不同銀組成之 La0.７Sr0.3-xAgxMnO3 (其中x=0、0.1、0.2、0.3)固態氧化物，探討其作為燃料電池陰極觸媒之可行性。實驗時，調整鍶與銀的藥品比例、前驅粉體的煆燒溫度等因素，研究其形成觸媒時的結晶性質、表面形貌、熱性質分析、電化學性質等，以評估作為燃料電池陰極的可行性。 本研究利用X光繞射分析儀（XRD），來討論合成出來的新型陰極材料的結晶結構及型態，並進一步使用TOPAS（Total pattern analysis solution）軟體進行定量及結晶學分析，並使用掃描式電子顯微鏡（SEM）來探測其微結構、形貌及半定量分析，利用熱分析儀（TGA、DSC）來觀察陰極粉體煆燒時的變化來推斷其燒結過程有無差異，再使用X光光電子能譜儀（XPS）來討論銀價態之變化，最後再將陰極材料製備成全電池，以直流電極化曲線（I-V curve）和電化學阻抗頻譜圖（EIS）來評判電池的性能。 結果發現當銀含量在x=0.0~0.2間均可形成鈣鈦礦結構，但當x?0.2時會發現些許銀的雜相，同在操作溫度900oC下，銀含量在x=0.2時所具有的最佳電流功率（227mW/cm2）較銀含量x=0.0（102mW/cm2）時要來的優異。 Precursors of La0.7Sr0.3-xAgxMnO3 (x = 0, 0.1, 0.2, 0.3) prepared by co-precipition of two solutions of nitrate salts and potassium hydroxide and their calcination under various temperatures to make of cathode catalysts for their use in solid oxide fuel cells (SOFC) were of interest. The effects of Sr/Ag molar ratio in the nitrate solutions and calcination temperature on the morphology, composition and crystalline structure of the catalysts and on the character such as specific surface area, thermal property and cathodic behavior applied in SOFC were focused. The morphology and composition of the oxide powders and catalysts were examined through field emission scanning electron microscope (FE-SEM) equipped with energy dispersive x-ray analysis (EDS). The crystal structure was determined by X-ray diffractometer (XRD) and further delineated in detail with the commercial software named as total pattern analysis solution (TOPAS). The gravimetrical and thermal properties of various precursors in calcination process were determined by thermal gravimetrical analysis (TGA) and Differential Scanning Calorimeter (DSC). The composition of the surface films on the oxides was explored by X-ray photoelectron spectroscopy (XPS) that is useful to verify the chemical states of Ag-component. Different cathode catalysts were made of various oxides to assembly a single cell on the purpose for evaluation its efficiency by the performance of I-V polarization and electrochemical impedance spectroscopy (EIS). Resulting from various tests, the oxides La0.7Sr0.3-xAgxMnO3 (x = 0, 0.1, 0.2, 0.3) still retained in a perovskite structure with silver content ranging in x=0.0 ~ x=0.30. However, an impurity phase of metallic silver was present if x ? 0.2. Electrochemical tests led to a conclusion: the power density is the highest (227mw/cm??2) for the best cathode catalysts made of the oxide with x = 0.2 as compared to that (102mw/cm2) made of the oxide free from silver (i.e., x = 0.0)
