Effect of Monovacancy Defects on Adsorbing of CO, CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt;, NO and NO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; on Carbon Nanotubes: First Principle Calculations

Ahlam A El-Barbary,Afaf M Babeer,Gehan H Ismail

doi:10.4236/jsemat.2013.34039

Abstract

We have applied density functional theory to investigate different types of carbon nanotubes (armchair (4,4)CNT and zig-zag (7,0)CNT) as sensors of some pollutant gas molecules, especially CO, CO2, NO and NO2. We show, for the first time, that the adsorption of pollutant gas molecules on carbon nanotubes are improved by introducing the monovacancy defects on the surfaces of (7,0)CNT. The adsorption energies, the optimal adsorption positions and the orientation of these gas molecules on the surfaces of carbon nanotubes are studied. It is found that the most adsorbed pollutant gas is NO molecule on (7,0)CNT.

Highlights

More than a decade after the discovery of carbon nanotubes (CNT) by Iijima in 1991 [1], they are still one of the hottest research areas in all of science and engineering
For the first time, that the adsorption of pollutant gas molecules on carbon nanotubes are improved by introducing the monovacancy defects on the surfaces of (7,0)CNT
We have studied the effect of gas molecules orientation by adsorbing CO and NO, once when the oxygen atom is faced the surface of (4,4)CNT and the other when the carbon/nitrogen atom is faced the surface of carbon nanotube

Summary

Introduction

More than a decade after the discovery of carbon nanotubes (CNT) by Iijima in 1991 [1], they are still one of the hottest research areas in all of science and engineering. The specific geometry and unique properties of carbon nanotubes suggest important potential applications including transistors, hydrogen storage devices, quantum dots, gas sensors, and so many other applications [2,3,4,5]. Gas adsorption on carbon nanotubes is a great issue for both essential research and applied application of nanotubes. The most widely used consideration of atomistic modeling of a CNT is by reference to rolling up graphene sheet to form a hollow cylinder with end caps. The cylinder is composed of hexagonal carbon rings, while the end caps of pentagonal rings.

Methods

Results

Conclusion