SnO2/KNN纳米纤维的力电耦合效应与主动式氢敏机理研究

The safe and accurate hydrogen detection is the premise for the safe application of hydrogen energy. Aiming at the lagged passive sensing response and uneasy maintenance to the power supply system of the hydrogen sensors, this proposal is proposed to use SnO2-modified potassium sodium niobate (KNN) piezoelectric nanofibers to realize the active hydrogen detection, and fabricate the self-powered hydrogen sensor through the electromechanical coupling between the gas flow and nanofibers in microfluidic chips. Firstly, SnO2/KNN nanofibers will be prepared by the electrospinning and sintering process. The impact of synthesis process to the size, morphology and interface atom structure of the SnO2 layers will be studied. Then the influence of surface modification on the hydrogen sensing, electric transportation, dielectric and piezoelectric properties of the nanofibers will be investigated to analyze the regulation mechanism for the room-temperature hydrogen sensing and electromechanical conversion properties of the SnO2/KNN nanofibers. After that, the electromechanical coupling effect between the gas flow and the nanofibers in the micro channels will be studied. The relationship among the chip structure, gas flow behavior and the electromechanical conversion performance will be investigated to realize the high efficient energy conversion and obtain the self-powered hydrogen sensors with fast, sensitive and stable sensing performance. The smooth implementation of this project can provide theoretical and experimental basis for the research and development of self-powered hydrogen sensor, which is also of great significance to promote the miniaturization and integration of sensor systems as well as the safe application of hydrogen energy.

实现安全准确的氢气检测是氢能安全应用的前提。针对氢气传感器被动检测时响应滞后及供电系统不易维护等问题，本项目拟采用SnO2修饰的铌酸钾钠(KNN)压电纳米纤维实现主动式氢气检测，结合微流芯片中待测气体与纳米纤维的力-电耦合构建自供电氢气传感器。首先，采用静电纺丝和烧结法制备SnO2/KNN纳米纤维，研究制备工艺对SnO2修饰层尺寸、形貌和界面原子结构的影响，探索表面修饰与纳米纤维氢敏特性、电输运行为和介电压电性能的关联性，分析纳米纤维室温氢敏和机电转换性能的调控机理，优化自供电氢敏性能。然后，研究气流和纳米纤维在微流通道中的力-电耦合效应，分析芯片构型、气流行为和纤维机电转换性能的关系，实现高效机电能量转换，获得快速灵敏且稳定可靠的自供电氢气传感器。本项目的顺利实施，将为自供电氢气传感器的研制提供理论和实验依据，对促进传感系统小型化和集成化，推动氢能的安全应用具有重要意义。

随着传感器件的尺寸不断降低，锂离子电池等传统供电单元已无法满足传感系统集成化、智能化发展的需求，自供电传感系统的研发已成为传感器领域研究人员关注的焦点之一。本项目采用静电纺丝技术先后实现了(K,Na)NbO3（KNN）、NaNbO3(NN)和聚偏氟乙烯(PVDF)等多种压电纳米纤维的可控制备，利用水热合成法生长了KNN单晶纳米棒阵列和SnO2单晶纳米棒微纳结构，并制备了SnO2纳米颗粒修饰的KNN纳米棒阵列和纳米纤维等复合材料。通过优化材料制备工艺、改善退火条件等方法，分别实现了KNN和PVDF纳米纤维和纳米棒阵列的压电性能优化，所得KNN纳米棒阵列的径向压电常数达到360 pm/V。在此基础上，首先探索了KNN、NN和PVDF纳米纤维及KNN纳米棒阵列在固态条件下的压电能量收集特性，获得了输出电压达到2-10V的多种压电能量收集器件，并实现了对动态应变的幅度和频率的自供电探测。其次，分析了SnO2单晶纳米棒的室温氢敏性能，发现在材料经真空退火后对氢气的室温响应灵敏度可达100以上，且响应时间短、恢复快、选择性好。然后，结合有限元仿真设计并构建了基于压电纳米纤维的微流控能量收集器件，探明了微流控芯片的沟道结构、尺寸对器件能量收集特性的影响规律，分别实现了对液、气单相和两相流体的微能量收集，获得了自供电微流体压强和粘度传感器件。最后，通过分析不同湿度和光照条件下，NN纳米纤维和SnO2/KNN纳米棒阵列的压电能量收集特性的变化，获得了自供电湿度传感器和紫外线传感器件。所得研究成果可为自供电传感器件和智能传感系统的研究与开发提供理论依据和实验基础，推动我国智能传感领域的发展。