使用一步化多元醇法經由段燒過程製備鈀奈米粒子/棒狀二氧化鈦/還原型氧化石墨烯(Pd NPs/TiO2 MRs/RGO)複合材料,並於氧化鋁基板上直接製備室溫型氨氣感測器,並利用掃描式電子顯微鏡(SEM),分析鈀奈米粒子與還原型氧化石墨烯在棒狀二氧化鈦表面的分布情況與結構組成,穿透式電子顯微鏡(TEM)、X射線繞射儀(XRD)確定其材料組成與晶格結構,再藉由傅立葉紅外線光譜(FTIR)、拉曼光譜儀(Raman)鑑定Pd NPs/TiO2 MRs/RGO複合材料含有的官能基與石墨烯的還原程度,證明Pd NPs/TiO2 MRs/RGO複合材料成功透過一步化多元醇法製備完成。
將製備好的Pd NPs/TiO2 MRs/RGO複合材料通入氨氣測試的結果顯示,鈀奈米粒子/棒狀二氧化錫鈦/還原氧化石墨烯三元素複合薄膜在室溫下對於氨氣偵測有著最好的感測靈敏度,比單純棒狀二氧化鈦薄膜或棒狀二氧化鈦/還原型氧化石墨烯薄膜較佳,並具有較低的偵測極限(~5ppm),此外,其感測元件擁有良好的選擇性與再現性、反應時間與回復時間短等優點。透過鈀奈米粒子的催化特性以及二氧化鈦與還原型氧化石墨烯所形成的n型半導體,來探討氨氣的感測機制。
Pd nanoparticles (Pd NPs), TiO2 microrods (TiO2 MRs) and reduced graphene oxide (RGO) ternary composite (Pd NPs/TiO2 MRs/RGO) film were fabricated by one-pot polyol, followed by annealing, to yield two morphologies of MRS and NPs. The NH3 gas-sensing properties of Pd NPs/TiO2 MRs/RGO film at room-temperature were investigated. The morphology, phase composition and crystalline structure of Pd NPs/TiO2 MRs/RGO ternary composite films were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffractometry (XRD), Fourier transform infrared spectroscopy (FTIR) and Raman spectroscopy. Microstructural observations revealed that the Pd NPs and interconnected TiO2 MRs randomly adhered to the surface of RGO. Comparative gas sensing results revealed that the sensor that was based on the Pd NPs/TiO2 MRs/RGO ternary composite film responded much more strongly to NH3 gas at room temperature than did that based on TiO2 MRs and TiO2 MRs/RGO films, revealing the contribution of RGO and Pd NPs to NH3 gas-sensing capacity. Most importantly, the sensor that was made of the Pd NPs/TiO2 MRs/RGO ternary composite film responded strongly to low concentrations of NH3 gas at room temperature; its use is practical because of its ease of fabrication.