Adsorption of CO molecules on doped graphene: A first-principles study

Yang Chai,Weidong Wang,Cuili Shen,Yuxiang Zhang

doi:10.1063/1.4942491

Abstract

As a typical kinds of toxic gases, CO plays an important role in environmental monitoring, control of chemical processes, space missions, agricultural and medical applications. Graphene is considered a potential candidate of gases sensor, so the adsorption of CO molecules on various graphene, including pristine graphene, Nitrogen-doped graphene (N-doped graphene) and Aluminum-doped graphene (Al-doped graphene), are studied by using first-principles calculations. The optimal configurations, adsorption energies, charge transfer, and electronic properties including band structures, density of states and differential charge density are obtained. The adsorption energies of CO molecules on pristine graphene and N-doped graphene are −0.01 eV, and −0.03 eV, respectively. In comparison, the adsorption energy of CO on Al-doped graphene is much larger, −2.69 eV. Our results also show that there occurs a large amount of charge transfer between CO molecules and graphene sheet after the adsorption, which suggests Al-doped graphene is more sensitive to the adsorption of CO than pristine graphene and N-doped graphene. Therefore, the sensitivity of gases on graphene can be drastically improved by introducing the suitable dopants.

Highlights

Because solid-state gas sensors have high sensitivity, wide range of applications and low cost,[1] a new generation of gas sensors has been demonstrated using carbon nanotubes (CNTs) and semiconductor nanowires in the past few years.[2]
Our results show that there occurs a large amount of charge transfer between CO molecules and graphene sheet after the adsorption, which suggests Al-doped graphene is more sensitive to the adsorption of CO than pristine graphene and N-doped graphene
The carbon-nitrogen atom distance is found to be 1.41 Å for N-doped graphene, and the carbon-aluminum atom distance 1.71 Å for Al-doped graphene, which are in agreement with previous theoretical work in Al-doped single wall carbon nanotubes (SWCNTs) and Al-doped graphene.[25,26,27]

Summary

INTRODUCTION

Because solid-state gas sensors have high sensitivity, wide range of applications and low cost,[1] a new generation of gas sensors has been demonstrated using carbon nanotubes (CNTs) and semiconductor nanowires in the past few years.[2]. Most of the previous work focused on pristine graphene, and predicted relatively low adsorption energies in comparison with the essential requirement of gas sensing applications.[10,11,12] It was reported that the detectable range and sensitivity of the single wall carbon nanotubes (SWCNTs) could be widened and improved through doping technology.[4,13,14] SWCNT coated with Pb nanoparticles has high sensitivity to H2,14 and SnO2/SWCNTs hybrid material shows an enhanced sensitivity to NO2.14–16 in order to improve the sensitivity for gases in graphene, doping is a kind of good methods.

MODELING AND COMPUTATIONAL DETAILS

RESULTS AND DISCUSSIONS

SUMMARY