Enhancement effect of Ni and NiO on gas sensing characteristics of carbon nanotube based structures.

In the presented work, the effect of nickel (Ni) and nickel oxide (NiO) nanoparticles on the sensing properties of multi-walled carbon nanotubes (MWCNTs) was studied. The sensor structure, developed on the basis of MWCNTs functionalized with oxygen containing groups, shows 10% sensitivity to nitrogen dioxide (NO2 gas) within 30 s, and the resistance increases under the influence of both oxidizing (NO2) and reducing (NH3) gases. However, after the decoration of the functionalized MWCNTs f-MWCNTs with Ni and NiO their sensing response to NO2 gas at room temperature were recorded 60% (within 20 s) and 107% (within 7 s), respectively and the selectivity was improved many times. The sensing mechanisms of the fabricated f-MWCNTs/Ni and f-MWCNTs/NiO-based sensor structures were explained from physical and chemical viewpoints. It was determined that both Ni and NiO play catalytic roles in the sensing processes of the fabricated f-MWCNTs/Ni and f-MWCNTs/NiO-based sensor structures. [ABSTRACT FROM AUTHOR]