Comparative Study of Adsorption of O₂, CO₂, NO₂and SO₂ on Pristine and Si-Doped Carbon Nanotubes

Abstract

Density functional theory is used to investigate the adsorption properties of O2, CO2, SO2 and NO2 gas molecules on pristine carbon nanotube (CNT) and Si-doped carbon nanotube (Si-CNT). All molecules except NO2 are physisorbed, with essentially no charge transfer between the CNT and molecules. The electronic properties of CNT are sensitive to the adsorption of NO2 because of its chemisorption, while they are insensitive to the O2, CO2 and SO2 molecules. The weak binding of these molecules on CNT is due to formation of charge-dipole interactions. In case of Si-CNT, all molecules are chemisorbed to the Si-C bonds with appreciable adsorption energy and significant charge transfer. The density of state analysis shows that the additional state near the Fermi level due to doping of silicon is responsible for chemisorption of the molecules. Further, our theoretical results suggest that molecule-induced modification of the density of states close to the Fermi level might significantly affect the transport properties of nanotubes.

A Molecular View of Adsorption on Nanostructured Carbon Materials

“…311 The weak binding of these molecules on CNT is due to formation of charge-dipole interactions. In case of Si-CNT, all molecules are chemisorbed to the Si-C bonds with appreciable adsorption energy and significant charge transfer.…”

Dopamine detection by doped single-walled carbon nanotube biosensors: A theoretical study

“…Also, they investigated interfering effect of biological molecules like ascorbic acid (AA) in determining dopamine and have not observed anyinterference signal from ascorbic acid (AA) during DA etection. Ab initio first principles methods have been used to probe the adsorption mechanism of NO2 gas on M-doped (Ti, Cu, and Pt) SWCNT (8,0) to determine the most efficient combination for NO2 sensing [27]. A density functional theory (DFT) study has been performed on Rh-doped CNT biosensors for prediagnosis of lung cancer and detection of CO2, C6H6 and C6H7N gases [28].…”