Modeling the Sensing Activity of Carbon Nanotubes Functionalized with the Carboxyl, Amino, or Nitro Group Toward Alkali Metals

Abstract

The sensing activity of carbon nanotubes (CNTs) functionalized with the carboxyl, amino, or nitro group toward the atoms and ions of different metals are modeled using the semiempirical modified neglect of the diatomic overlap (MNDO) and density functional theory (DFT) methods. We discuss the mechanism by which the functional groups attach to the open end of a zig-zag type CNT to form a probe for chemical sensing. The interaction of the CNT-based probe with the potassium, sodium, and lithium atoms and ions is considered in detail. By comparing the results of the modeled sensing activity of the nanoprobes toward the elements of interest, we determine the optimal functional group for the CNT modification to produce a sensor suitable for identifying the potassium, lithium, and sodium atoms and ions, including those that occur in salts and alkali salts.