MIL-125(Ti)及其氨基功能化材料修饰石英晶体微天平的湿敏性能

采用简单的溶剂热法制备金属有机框架化合物MIL-125(Ti)和NH_2-MIL-125(Ti)材料,并通过X射线衍射仪、扫描电子显微镜、傅氏转换红外线光谱分析仪和比表面积测试仪对所得样品进行表征。将2种材料修饰构建为石英晶体微天平传感器,测试其在11%～97%RH相对湿度范围内的湿度感测性能。实验结果表明,基于MIL-125(Ti)和NH_2-MIL-125(Ti)构建的传感器对湿度具有灵敏度高、重复性好、响应/恢复快等特点。相对于没有氨基修饰的MIL-125(Ti),NH_2-MIL-125(Ti)材料修饰的传感器对湿度表现出更高的响应性能。在环境湿度约52%时,NH_2-MIL-125(Ti)传感器对11%RH湿度响应值比MIL-125(Ti)湿度传感器的大57 Hz,说明氨基功能化对MIL-125(Ti)的湿敏性能有显著的增强作用。此外,通过Materials Studio模拟计算获得了水分子与MIL-125(Ti)及NH_2-MIL-125(Ti)作用的吸附焓,也证明氨基功能化对MIL-125(Ti)的湿度敏感性能具有增强作用。

Amino-Functionalization and Enhanced Humidity Sensing Properties of MIL-125 Based on Quartz Crystal Microbalance Sensor

The metal organic framework compounds MIL-125(Ti) and NH₂-MIL-125(Ti) were prepared and chara-cterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR)and specific surface area (BET). The humidity sensing performances of the two materials based QCM sensors were studied by exposed to humidity range of 11%~97%RH (relative humidity). The experimental results show that the MIL-125(Ti) and NH₂-MIL-125(Ti) sensors have some advantages, such as high sensitivity, good repeatability, fast response/recovery and etc. Compared with MIL-125(Ti), the sensor modified by NH₂-MIL-125(Ti) exhibited higher response to humidity.when the indoor humidity was about 52%, the frequency shift of the NH₂-MIL-125(Ti) sensor to a 11% relative humidity was 57 Hz higher than MIL-125(Ti), indicating that the amino-functionalized material had a certain enhancement to the response of the humidity sensor. Furthermore, the adsorption enthalpys between water molecules and MIL-125(Ti) or NH₂-MIL-125(Ti) was obtained by Materials Studio, which proved that the amino functionalization could enhance the humidity sensitivity of MIL-125(Ti).