Detection of Environmentally Toxic Molecules Using Carbon Nanotubes: A First-Principles Theoretical Study

Abstract

The adsorption process of environmentally harmful (CO2), toxic (CO, NO and NO2) and common (O2 and N2) molecules in air on boron and nitrogen-doped carbon nanotubes (CNTs) and its effects on quantum transport are studied using the first-principles density-functional calculations combined with the quantum transport method. It is found that CO, NO, NO2 and O2 molecules can strongly bind on the B-doped (10,0) CNTs while only NO and NO2 molecules are strongly adsorbed on the N-doped (10,0) CNTs in air. Quantum transport properties of (10,0) CNTs regarding the adsorption of the molecules are quantitatively investigated, and it is found that the adsorption of the molecules changes sizably the quantum conductance of the CNTs, which depends on the types of the adsorbed molecules. The origin associated with the wide variation of the quantum conductance induced by the molecular adsorption is revealed, and the possibility to selectively detect toxic CO, NO, and NO2 molecules in air is discussed.