本研究利用電沉積法，在FTO導電玻璃上製備二氧化錫薄膜，透過不同的製備條件，分別為：沉積電位、硝酸濃度、沉積溫度、沉積時間及退火溫度，尋求二氧化錫薄膜光催化降解甲基橙之最佳化條件。再來利用光還原法 (Photoreduction method) 沉積銀在二氧化錫表面上，在光還原法中，藉由控制硝酸銀濃度與照光時間，找出銀/二氧化錫 (修飾銀於二氧化錫表面上) 薄膜光催化降解甲基橙之最佳化條件。
二氧化錫薄膜、銀/二氧化錫薄膜的性質鑑定，分別經由X射線繞射分析儀 (X-ray diffractometer, XRD) 觀察晶體結構，掃描式電子顯微鏡 (Scanning electron microscopy, SEM) 觀察表面形貌，以及能量分散式光譜分析儀 (Energy dispersive spectrometer, EDS) 進行元素組成分析，使用8 W 254 nm長型紫外光燈作為光源進行光催化降解甲基橙之實驗，並搭配光纖可見光光譜儀測量其吸收值來計算降解率。
由實驗結果得知，以25 mM 氯化亞錫與100 mM硝酸所組成之電解液，固定沉積電位 -0.8 V、沉積溫度80℃、沉積時間30 mins、無須退火之二氧化錫薄膜光催化甲基橙降解率為38.3%。為了提高二氧化錫薄膜之光催化甲基橙降解率，在二氧化錫表面上修飾銀，其中，光還原銀條件為硝酸銀10 mM，照光時間60 s，銀/二氧化錫薄膜光催化甲基橙降解率提高至49.1%。

In this work, the fabrication of tin oxide (SnO2) thin film was deposited on fluorine-doped tin oxide (FTO glass) by chronoamperometry. To optimize deposition conditions, different parameters we discussed including the potential of deposition, the concentration of nitric acid, deposition temperature, deposition time and annealing temperature. We discussed the degradation rate by photocatalytic degradation of methyl orange (MO). Photodegradation of MO is using 254 nm UV lamp as a light source. After the reaction, the absorbance of MO was measured by a fiber visible spectrometer to calculate the degradation rate. In addition, to improve the photocatalytic degradation rate of SnO2 thin film, silver was deposited on the surface of SnO2 by the photoreduction method. We control the concentration of silver nitrate and ultraviolet light irradiated time to fabricate Ag/SnO2 thin film. The properties of SnO2 thin film and Ag/SnO2 thin film were characterized by using X-ray diffractometer (XRD), scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS). Adding silver to the surface of SnO2 thin film can prevent the electron-hole pairs from rapidly recombining. That effectively enhances the degradation rate. Finally, the degradation rate of MO increased from 38.3% to 49.1%.

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