四氟化碳（CF₄）為半導體製程中常見之氣體，具有高化學穩定性、全球暖化潛勢及大氣停留時間長等特性，若未妥善處理排放至大氣中，將對全球暖化造成影響，由於CF₄分子中碳氟鍵鍵能高使其難以被分解，傳統處理方法包括燃燒、熱催化及熱電漿，上述方法常伴隨高能耗、設備成本高及觸媒失活等問題，因此本研究以介電質放電（dielectric barrier discharge， DBD）非熱電漿結合觸媒系統處理CF₄，並探討不同觸媒材料與操作條件對CF₄轉化率、能量效率及產物之影響，以評估電漿觸媒系統應用於CF₄去除之可行性。本研究以γ-Al₂O₃為載體，分別搭載Ce與Zn金屬活性相，並以硫酸根進行表面改質，並比較不同鍛燒時間對觸媒性質與CF₄去除效率之影響，其中搭載Ce金屬活性相之觸媒表面具有Ce³⁺/Ce⁴⁺混合價態，有助於形成氧空缺與表面活性氧物種提升去除效率，搭載Zn金屬活性相之觸媒表面形成尖晶石結構，提升觸媒結構穩定性與增強表面Lewis酸性位點，於電漿觸媒系統中ACS觸媒受鍛燒時間影響較明顯，其中鍛燒10小時之ACS觸媒於Ar 90%、總流量50 mL/min及頻率15.5 kHz條件下，在11 kV時可達最高CF₄轉化率為98%，並於9 kV時達到最高能量效率為1.4 g/kWh，為本研究最佳操作條件，相較之下AZS觸媒之CF₄轉化率與能量效率受鍛燒時間影響較小。OES光譜分析結果顯示電漿反應過程中可觀察到N₂ second positive system、N₂⁺ first negative system、N₂ first positive system、OH、Hα、Hβ、CO、F、O I及Ar I等特徵峰，FTIR分析結果則顯示，CF4反應後主要生成CO、HF與H₂O(g)。本研究結果顯示，DBD電漿觸媒系統具有良好之CF₄轉化率與能量效率，其可於常溫操作之特性具有降低能耗之潛力。;Tetrafluoromethane (CF₄) is widely used as an etching gas in semiconductor manufacturing processes. It has high chemical stability， a high global warming potential， and a long atmospheric lifetime. Therefore， emission of CF₄ into the atmosphere may aggravate global warming. The high bond energy of the C–F bonds in CF₄ makes it difficult to decompose. Conventional treatments， such as combustion， thermal catalysis， and thermal plasma treatment， are often associated with high energy consumption， high costs， and catalyst deactivation. In this study， a dielectric barrier discharge (DBD) non-thermal plasma system coupled with catalysts was used for CF₄ decomposition， and the effects of different catalysts and operating conditions on CF₄ conversion， energy efficiency， and product formation were investigated to evaluate the plasma catalysis systems for CF₄ removal. In this study， γ-Al₂O₃ was used as the catalyst support and was loaded with Ce and Zn as metal active phase， followed by surface modification with sulfate. The effects of different catalyst calcination times on CF₄ removal efficiency were compared. The Ce metal active phase catalysts have Ce³⁺/Ce⁴⁺ oxidation states on the catalyst surface， which may form oxygen vacancies and enhance CF₄ removal efficiency. In contrast， the Zn metal active phase catalysts formed a spinel structure， which improved structural stability and enhanced surface Lewis acid sites. In the plasma catalysis system， the ACS catalyst was more effected by calcination time. The ACS catalyst calcined for 10 h had the best performance with 90% Ar， a total flow rate of 50 mL/min， and a frequency of 15.5 kHz. The highest CF₄ conversion of 98% was achieved at 11 kV， and the maximum energy efficiency of 1.4 g/kWh was achieved at 9 kV. In comparison， the CF₄ conversion and energy efficiency of the AZS catalysts were less effected by calcination time. Optical emission spectroscopy (OES) showed that characteristic peaks corresponding to the N₂ second positive system， N₂⁺ first negative system， N₂ first positive system， OH， Hα， Hβ， CO， F， O I， and Ar I were observed in the plasma reaction. These results indicate generated from the excitation of N₂， H₂， CF₄， O₂， CO₂， and Ar in the system. Fourier-transform infrared spectroscopy (FTIR) analysis indicated products were CO， HF， and H₂O. Overall， the results demonstrate that the DBD plasma catalysis system achieved high CF₄ conversion and energy efficiency. Its operation at room temperature has potential for reducing energy consumption.
