以rGO/α-Fe2O3發展室溫下之石英晶體微天平式二氧化氮感測器

近年來科技發展日新月異，人們生活品質及身體健康受到重視，許多有毒氣體充斥在生活環境中，其中二氧化氮為常見有害氣體之一，經由石化燃燒及汽機車廢氣排放所形成，抑或是工業製造硝酸時之中間產物，每年約有幾百萬噸二氧化氮排放到大氣中。一般來說，二氧化氮在室溫下呈現紅棕色，且帶有刺鼻的氣味，若不經意情況下吸入，在低濃度情況下，將造成肺部灼傷；高濃度情況下，將大幅提高呼吸道病變之機率。此外二氧化氮導致許多環境汙染，常見汙染種類，如：酸雨、光化學煙霧及部分金屬之氧化。在經濟發展與環境保護之間必須取得平衡點，所以監控二氧化氮排放量及濃度顯得相當重要。石英晶體微天平應用於氣體感測器具良好穩定度、靈敏度及重現性，適合發展成二氧化氮氣體感測器。本研究使用共振頻率為18.432 MHz之AT cut石英振盪器，並在上表面電極塗佈還原氧化石墨烯結合氧化鐵之感測材料，能直接室溫下量測二氧化氮，無需使用加熱器，利用石英晶體微天平對質量負載效應之敏銳度及線性度，並設計雙埠延遲線能有效降低溫度及濕度等環境擾動；此外，為了提高塗佈感測材料之均勻性，嘗試三種不同塗佈製程並測試頻率訊號之穩定度，根據結果，在使用超聲波噴塗製程下，頻率訊號穩定度最高。二氧化氮量測方面，將量測三次回復曲線，確保感測器有良好的重複性，並量測濃度108、217、347及500 ppm，在濃度0~217 ppm時，靈敏度達1.7306 Hz/ppm；在濃度217~500 ppm時，靈敏度達0.4576 Hz/ppm，證明結合還原氧化石墨烯/氧化鐵之石英晶體微天平適合發展成二氧化氮氣體感測器。

關鍵字

石英晶體微天平；二氧化氮感測器；還原氧化石墨烯/氧化鐵；雙延遲線；超聲波噴塗

並列摘要

In recent years, the development of technology has become better and better. People care about the quality of life and the health of body. Lots of toxic gases are filled with in our environment. Among them nitrogen dioxide is one of the most common harmful gases. Nitrogen dioxide will be exhausted several million tons every year. That situation is caused by burning fossil fuel, exhaling gases by cars, and producing nitric acid. In general, nitrogen dioxide is red-brown color at room temperature and smells pungent. Sometimes, people will breathe in nitrogen dioxide carelessly. If the nitrogen dioxide concentration is low, lung will get burned. If the nitrogen dioxide concentration is high, the possibility of respiratory tract lesion will enhance. Nitrogen dioxide results in many environmental pollution, like acid rain and photochemical smog. Finding a balance between development of economy and protection of environment is essential. Therefore, monitoring nitrogen dioxide emission and concentration is quite important. Quartz crystal microbalance(QCM) is suitable to be gas sensor because QCM applying to gas sensor has great stability, sensitivity, and repeatability. In this thesis, QCM, operating frequency at 18.432 MHz based on AT cut quartz is coated with rGO/α-Fe2O3 on the surface of electrode. The gas sensor can operate at room temperature without a heater. QCM is sensitive to mass loading and has linearity. Dual channel configuration is employed to eliminate temperature and humidity fluctuations. The stability of frequency signals of three different coating processes is conducted to evaluate the performance of sensor. Every curve of measurements repeats three times to confirm repeatability of gas sensor. According to the measurements, ultrasonic spraying has the best stability. When concentration of nitrogen dioxide is between 0 and 217 ppm, the sensitivity of QCM reaches 1.7306 Hz/ppm. When concentration of nitrogen dioxide is between 217 and 500 ppm, the sensitivity of QCM reaches 0.4576 Hz/ppm. It proves that QCM coated with rGO/α-Fe2O3 is proper to be developed as a gas sensor.

並列關鍵字

QCM ； Nitrogen dioxide sensor ； rGO/α-Fe2O3 ； Dual channel configuration ； Ultrasonic spraying

參考文獻

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以rGO/α-Fe2O3發展室溫下之石英晶體微天平式二氧化氮感測器

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