Effect of structure and morphology of carbon nanotubes on NO2 gas sensing

Abstract

In this research, we investigated the effect of structure and morphology of carbon nanotubes (CNTs) on nitrogendioxide (NO2) gas sensing. CNTs were synthesized by thermal chemical vapor deposition (TCVD) at different synthesistemperatures. The structure and morphology of CNTs were investigated by various characterization tools such as scanningelectron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. The resistance changes ofCNTs were obtained upon NO2 gas exposure with concentrations of 600, 1,800 and 3,000 ppm at room temperature. Ourresults show that the CNTs prepared at 950°C showed the highest response. We suggest that the response of CNTs to NO2gas depends more strongly on the interstitial area and electronic structure than on the defects of CNTs. These results are ingood agreement with the theoretical calculations on adsorption sites (surface, pore, groove and interstitial) and electronicstructure (metallic or semiconducting) reported by previous studies.

Keywords

• carbon nanotubes
• thermal chemical vapor deposition
• gas sensor
• catalytic particles