MWCNTs/多孔ZnO纳米材料的制备及室温NO气敏性研究

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

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.

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 nan- opartieles. The sensor response of the composites to NO was examined at room temperature with a relative hu- midity 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. Hy- brid material with 200 mg MWCNT -- COOH exhibits higher response than other hybrid materials for NO de- tection at low concentrations （ ≤ 50×10-6）.