基于自组装金钯核壳纳米颗粒单层膜的光纤H_(2)传感器

Optical fiber hydrogen sensor based on self-assembled of Au@Pd NPs monolayer film

低维纳米材料的大比表面积极大提升了材料与环境气体分子的反应效率,对提高光纤氢气传感器中关键氢敏器件的灵敏度及响应速度有着至关重要的作用。提出了一种在油水界面自组装制备高性能金钯(Au-Pd)核壳纳米颗粒单层氢敏薄膜的方法,并制备了基于该薄膜的透射式光纤氢气传感器。实验中采用水热合成法制备粒径约12 nm的球形Au核,然后在Au核水溶液中加入Pd生长液,得到粒径约为20 nm的Au-Pd核壳纳米颗粒。采用十八胺修饰Au-Pd核壳纳米颗粒并通过相转移技术将颗粒转移到甲苯溶液中,最后在甲苯-水界面提拉制备覆盖率高并且空洞和堆积少的纳米颗粒单层氢敏薄膜。表征分析结果表明,形成的Au-Pd核壳纳米颗粒粒径均匀且结晶度好,制备的纳米颗粒单层薄膜排列致密覆盖率达87%。搭建了透射式光纤氢气器并测试了制备的Au-Pd核壳纳米颗粒单层膜在不同氢气浓度下的感氢响应特性。实验结果表明,单层纳米颗粒氢敏膜对4%的氢气响应时间约为3 s,对0.1%的氢气(氮气为载气)响应时间约为13 s,在多个循环的测试中表现出良好的稳定性,该传感器在低浓度氢气的快速、准确检测上具有良好的应用前景。

The large specific surface area advantage of low-dimensional nanomaterials greatly improves the reaction efficiency between materials and environmental gas molecules,which plays a crucial role in im⁃proving the sensitivity and response speed of the key hydrogen-sensitive devices in fiber optic hydrogen sen⁃sors.In this paper,we describe a new method for the preparation of high-performance Au-Pd core-shell nanoparticle monolayer hydrogen-sensitive thin films by self-assembly at the oil-water interface as well as a transmission fiber hydrogen sensor based on the film.In the experiment,spherical Au nuclei with a parti⁃cle size of approximately 12 nm were prepared via a hydrothermal synthesis method.A Pd growth liquid was then added to the aqueous solution of Au nuclei to obtain Au-Pd core-shell nanoparticles with a particle size of approximately 22 nm.The Au-Pd core-shell nanoparticles were modified by octadecylamine and transferred to a toluene solution using phase transfer technology.Finally,nanoparticle monolayer hydro⁃gen-sensitive films with high coverage and fewer voids were prepared by pulling at the toluene-water inter⁃face.Characterization analysis results showed that the size of the Au-Pd core-shell nanoparticles formed was uniform with outstanding crystallinity,and the density coverage rate of the prepared nanoparticle monolayer film was 87%.A transmission fiber optic hydrogen apparatus was built to characterize the hy⁃drogen response characteristics of the prepared Au-Pd core-shell nanoparticle monolayer at different hydro⁃gen concentrations.The experimental results show that the nanoparticle monolayer hydrogen-sensitive thin film exhibits good stability in a number of cycle tests with high hydrogen response speeds(3 s to 4%of hydrogen and 13 s to 0.1%of hydrogen).The method of preparation of the sensor for rapid and accu⁃rate detection of low concentration of hydrogen has a good application prospect.