大气压介质阻挡放电对多壁碳纳米管表面改性及其气敏特性

H2S是气体绝缘组合电器(gas insulated switchgear,GIS)内部一些潜伏性绝缘缺陷产生放电的重要的特征组分气体之一,检测它对设备运行状态的诊断和评估有着重要的意义。为此,采用大气压介质阻挡放电(dielectric barrier discharge,DBD)等离子体对多壁碳纳米管(multi-walled carbon nanotubes,MWNTs)进行了表面改性。实验研究了改性前后MWNTs对体积分数为50×10-6的H2S标气的气敏特性的影响以及不同改性时间对其气敏特性的影响,结果表明,改性后的MWNTs对H2S在灵敏度和响应时间方面都有较大幅度的改善;改性时间为60s的MWNTs的气敏特性要优于其它时间。对处理前后的MWNTs进行了扫描电子显微镜(SEM)和傅里叶红外光谱(FTIR)分析,结果显示,经DBD等离子体处理后的MWNTs表面变粗糙,缺陷增加,其表面引入了羟基、羧酸根和C-O等含氧基团。

Surface Modification of Multi-walled Carbon Nanotubes by Dielectric Barrier Discharge in Atmospheric Pressure and the Analysis on Gas Sensitive Characteristics

H2S is one of important gas components through discharge which is caused by latent insulation infects in gas insulated switchgear(GIS).Therefore,detection of H2S is significant for the diagnosis and assessment of power equipment operating state.We utilized atmospheric pressure dielectric barrier discharge(DBD) plasma to modify the surface of multi-walled carbon nanotubes(MWNTs),experimentally investigated the sensitive characteristics of plasma untreated and treated MWNTs to room temperature H2S in 50×10-6,and investigated the influence of the treatment time on the gas sensitive characteristic l.The results show the plasma modified MWNTs can elevate the sensitivity and reactivity for H2S sensing,especially the MWNTs after 60 s treatment.Scanning electron microscopy(SEM) observation and Fourier transform infrared spectroscopy(FTIR) measurement indicate that,after atmospheric pressure air plasma treatment,the smooth MWNTs surfaces become rough,the surface defects of plasma-treated MWNTs are enhanced,and oxygen-containing groups are introduced onto MWNTs.