Sensitive detection of Nitrogen Dioxide using gold nanoparticles decorated Single Walled Carbon Nanotubes

Abstract

The modification of carbon nanotubes (CNTs) could enhance their surface and electric properties. To this purpose, we explore the impact of a thin layer of gold (Au) on the surface of single wall carbon nanotubes (SWCNTs). SWCNTs have been grown by Chemical Vapor Deposition (CVD) method and decorated with gold nanoparticles were investigated as gas sensitive materials for detecting nitrogen dioxide (NO2) at room temperature. Surface morphology and microstructure of Au-SWCNT have been characterized by FE-SEM and Raman Spectroscopy. Using the present collective approaches, the improvement in the detection of NO2 gas using Au-modified nanotubes is explained. However, Au-modified SWCNT gas sensors exhibited better performances compared to pristine SWCNTs. These changes in resistance and the shift of the Fermi level just after NO2 exposure was probably due to adsorption of NO2 molecules on the surface of Au-SWCNTs. Surface modification of nanotubes with understanding of sensing ability at atomic level opens the new way to design a selectivity gas sensor.