电流型乙炔气体传感器的研究

　　Study of Amperometric Acetylene Gas Sensors

　　LI Cui-ling1, SU Yi1, LV Xiang-yu1, SHI Hong-jun2, ZUO Yun-yun1, WANG Yu-jiang1

　　(1,Changchun Institute of Applied Chemistry, Chinese Academy of Science, Changchun, 130022

　　2,Liaoyuan Institute of Electronics and Technology, Liaoyuan, 136200)

　　Abstract: In this study, Au nanoparticles supported on multi-walled carbon nanotubes (Au-MWCNTs) were used as catalysts of this acetylene sensor. By using this catalysts, the cost was lowered and the performance was improved. The morphologis and structures of catalysts were characterized by transmission electron microscopy (TEM), Fourier Transform Infrared (FTIR) and X-ray Diffraction (XRD). Compared to the Au nanoparticles (Au-NPs), Au-MWCNTs showed good catalytic activity towards acetylene. The onset potential of Au-MWCNTs was 0.19 V more negative than Au-NPs and the peak current density was approximately two times of the Au-NPs. The amperometric acetylene sensor showed good detection results, with sensitivity of 80 nA/ppm and the response and recovery time less than 50 s. The acetylene sensor could be used in practical for the acetylene detection.

　　Keywords: Acetylene; sensors; gold nano; carbon nanotubes

　　0引言

　　乙炔(C2H2)是一种化学性质非常活泼的气体,极易燃烧、分解和爆炸,乙炔在空气中的爆炸范围为2.5%~80%，在氧气中含量达到2.3%~93%时,接触明火就会发生爆炸，在一定压力下有猛烈爆炸的危险，受热、震动、电火花等因素都可以引发爆炸。与其它易燃易爆气体相比,乙炔的爆炸范围大、爆炸下限低。因而,对乙炔污染源进行实时监测具有十分重要的意义[1-3]。再者，乙炔是变压器油中的故障特征气体,实时、准确地监测C2H2气体浓度对保障生产、生活的安全十分重要[3]。

　　目前乙炔气体的检测方法主要有光纤法[1,2]、光谱法[4]、气相色谱法等[5]。光纤气体传感器具有抗电磁干扰,传感单元结构简单,稳定可靠,可以实现光信号的长距离传输和现场实时遥测等优点，但由于光源造价一般很高,限制了它的大规模使用。色谱法的缺点在于需要现场采集样品，再到室内仪器上进行分析，操作复杂、不能满足快速实时在线检测、连续检测的要求[1,2]。因此，电化学传感器因为其廉价、简便易用、体积小、适于现场连续检测等优点而受到广泛的关注。本文就是利用电化学原理来实现乙炔气体的检测的。

　　乙炔的电氧化已经有了大量的研究，其中，金对乙炔的氧化表现出高的催化活性以及好的选择性[3]。催化剂载体对电化学器件的成本、性能以及稳定性等都有很大的影响，多壁碳纳米管有高的导电性、化学稳定性和机械强度等。基于此，本文用多壁碳纳米管负载金作为电氧化乙炔催化剂，希望得到成本低廉、高选择性、高灵敏度、低的检测限和方便易用的电流型乙炔气体传感器。