MWCNTs/多孔ZnO纳米材料的制备及室温NO气敏性研究

为开发室温气敏传感器材料,以Zn(NO3)2.6H2O为锌源、尿素为沉淀剂,在制备水合碱式碳酸锌(Zn4CO3(OH)6.H2O)的过程中加入羧基化的MWCNTs(MWCNT-COOH),焙烧制备了MWCNTs/ZnO复合材料.采用XRD,SEM和TEM等对其进行了分析.结果表明:复合材料中MWCNTs分散均匀,ZnO呈多孔纳米片状,纳米片由多个尺寸在10～20 nm的ZnO颗粒组成;在室温、空气湿度为50%的氛围中测试复合材料对NO的气敏响应发现,复合材料对体积浓度1×10-4的NO气敏响应灵敏度大约是MWCNT-COOH的3倍,明显高于MWCNT-COOH;对比加入不同量MWCNT-COOH制备的3种复合材料对NO的气敏性可知,加入200 mg MWCNT-COOH所制备的复合材料对低浓度(体积浓度≤50×10-6)的NO气体表现出较高的灵敏度.

Preparation of multi-walled carbon nanotubes-porous ZnO nanosheets composites and its gas sensor properties for NO detection at room temperature

To develop sensor materials at room temperature,multi-walled carbon nanotubes and ZnO composites were synthesized by using urea,zinc nitrate and carboxylated MWCNTs(MWCNT-COOH) as raw materials with homogeneous precipitation method and calcination.The structures and morphologies of the MWCNTs/ZnO composites were characterized by XRD,SEM and TEM.The results showed that a homogeneous distribution of MWCNTs in the composites was observed while ZnO existed as porous nanosheets consisting of many ZnO nanoparticles.The sensor response of the composites to NO was examined at room temperature with a relative humidity of 50%.The MWCNTs/ZnO sensor′s sensitivity was increased by a factor of three in comparison with that of MWCNT-COOH for NO at 1×10-4,because the porous ZnO nanosheets had larger surface area and the electron transfer between MWCNTs and ZnO could facilitate the decrease of the MWCNTs resistance.Hybrid material with 200 mg MWCNT-COOH exhibits higher response than other hybrid materials for NO detection at low concentrations(≤ 50×10-6).