钯纳米粒子多重散射耦合的高性能光纤氢气传感器研究

Optical fiber hydrogen sensor with the performance of trace detection and fast response is one of the core devices to protect the national hydrogen energy development strategy. However, the optical signal in the existing sensor is limited by the transmission mode. It leads to a problem that the coupling area is small, the efficiency is low and the loss is high. And there is a contradictory relationship between the sensitivity and response speed parameters of this sensor, which is difficult to optimize. In view of the above problems, this program proposes a hydrogen sensing mechanism that palladium nanoparticles couple into a spherical scattering cavity sensing structure. We plan to study the coupling characteristics between a large area of sensitive nanoparticles and multi-scattered light signals, to explore the relationship between the key parameters and the sensor response. This kind of hydrogen sensor can enhance the signal modulation ability of the material, while maintaining the fast response. Through above studies, we can find a new method to optimize the sensitivity and response speed of optical fiber hydrogen synergistically. This program focuses on the following contents: ① coupling modulation mechanism between palladium nanoparticles and multiple scattering optical signal; ② preparation and control methods of hydrogen sensitive nanoparticles coating; ③ sensor response characteristics and modeling optimization. This project will break through the coupling problem between the existing optical sensor and the sensitive material, which is of great significance to promote the development and application of high performance optical fiber hydrogen sensor.

具有痕量检测、快速响应性能的光纤氢气传感器是保障国家氢能发展战略实施的核心基础器件之一。但现有传感器件中光信号受到传输模式限制，与搭载的氢敏材料间普遍存在耦合面积小、效率低及损耗高的问题。导致传感器的灵敏度和响应速度参数间存在矛盾关系，难以同时优化。针对以上问题，本项目提出一种在球形散射腔传感结构中搭载钯纳米氢敏粒子的氢气传感机理；拟通过研究球腔内大面积均布氢敏粒子与多重散射光信号耦合的传感特性，揭示特征参数与感氢响应性能间的关系；在保持纳米尺度材料响应快速优势的同时增强材料光信号调制能力，探寻传感器灵敏度和响应速度协同优化的新方法。其中重点研究以下内容：①钯纳米粒子散射光信号耦合调制机理；②氢敏纳米粒子涂层的制备与调控方法；③传感器响应特性研究及建模优化。本项目将突破现有光传感器件与敏感材料间的耦合难题对传感性能优化的限制，对推动高性能光纤氢气传感器的发展和应用具有重要意义。

为了克服现有光纤氢气传感器件中光信号受到传输模式限制，与搭载的氢敏材料间普遍存在的耦合面积小、效率低及损耗高等问题。本项目提出了一种新颖的基于钯纳米粒子单层敏感膜的光纤氢气传感器，首先通过水相合成制备了粒径均一的金钯核壳结构纳米颗粒（粒径可调控范围14-32 nm），利用气-液界面自组装技术将金钯核壳纳米颗粒大面积组装成均匀致密的单层氢敏纳米薄膜。通过多种表征手段对不同制备参数的金纳米颗粒溶液、金钯核壳纳米颗粒溶液、氢敏纳米薄膜进行测量分析，探究影响成膜质量的镀膜参数，优化镀膜工艺。结果表明采用这种镀膜工艺可以得到粒径均匀且结晶度好的纳米颗粒和排列致密、覆盖率高、堆积少的纳米颗粒单层膜。然后，研究了空气中干扰气体的影响和钯基材料的失效老化原因，并提出通过沉积锌基沸石咪唑骨架（ZIF-8，孔隙尺寸0.34 nm）作渗氢阻氧保护层，克服了此种钯基薄膜在氧气环境下普遍存在的由于表层氧化导致的响应性能退化问题。最后，搭建了透射式氢气传感测试平台，完成了对不同制备参数的氢敏膜片的氢气响应性能测试，得到纳米颗粒膜在氮气环境下的响应性能。结果表明，金钯核壳纳米颗粒单层膜对4%的氢气响应速度约3 s，在多个循环的测试中表现出良好的稳定性。并且，涂覆有分子筛保护层的复合氢敏薄膜具有优异的响应/恢复速度、使用寿命和重复性。搭载有该氢敏薄膜元件的光纤氢气传感器可以极大发挥纳米颗粒材料比表面积大的优势，在保持纳米尺度材料响应快速优势的同时增强材料光信号调制能力，本项目将突破现有光传感器件与敏感材料间的耦合难题，膜层的多个参数（包括核、壳尺寸，颗粒形貌，排布层数及涂覆厚度等）均可实现调控，有利于对传感性能的优化，对推动高性能光纤氢气传感器的发展和应用具有重要意义。