Adsorption of gas molecules on a C3N monolayer and the implications for NO2 sensors

Zijia Zhao,Caitao Li,Song Hu,Yanmin Kuang,Yongliang Yong

doi:10.1063/1.5128803

Zijia Zhao, Caitao Li + Show 3 more

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https://doi.org/10.1063/1.5128803

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Abstract

Recent reports have raised exciting prospects for the use of C3N monolayers exhibiting excellent adsorptive properties in nanodevice applications. In this study, we carried out first-principle calculations to investigate the adsorption of NO2, NO, CO, HCN, NH3, CO2, H2, N2, CH4, H2O, O2, and N2O gas molecules on a C3N monolayer as well as its potential applications in gas sensor devices. Our results reveal that the chemisorption of NO2 can significantly influence the electronic properties of the C3N monolayer (e.g., changing semiconducting behavior to conducting behavior). In contrast, physisorption of the other gas molecules had little effect on the electronic properties of the C3N monolayer. These results suggest that the C3N monolayer is much more sensitive and selective to NO2 than to the other gases. The recovery time of NO2 at T = 300 K is only 0.62 s. Moreover, the optical properties of the C3N monolayer can be modified as a result of the adsorption of different molecules, especially the NO2 molecule. Thus, the C3N monolayer is a promising and desirable candidate for use as a suitable material in gas sensors for NO2 detection.

Highlights

Nitrogen dioxide (NO2), which is produced mainly in vehicle exhaust gases, from industrial byproducts, and in fuel combustion, is a toxic compound with a pungent odor that is harmful to the environment, being a major cause of acid rain and photochemical smog.1–3 the reactions of NO2 gas with moisture, ammonia, hydrocarbons, and other compounds generate minute particles, which can cause inflammation of the airways in human beings.4 In response to this increasing risk to health and to minimize the effects of prolonged NO2 inhalation, almost all countries have established regulatory and legislative standards to deal with this issue.5 For example, the European Commission suggests an hourly exposure to NO2 concentrations of no more than ∼106 ppb no more than 18 times per year
In order to explore the gas-sensing properties of C3N monolayers, we systematically investigated the adsorption behaviors and electronic properties of various gas molecules, including NO2, NO, CO, HCN, NH3, CO2, H2, N2, CH4, H2O, O2, and N2O, on C3N monolayers using the first-principles method based on density functional theory (DFT)
We investigated their band structures and densities of states (DOSs)

Summary

INTRODUCTION

Nitrogen dioxide (NO2), which is produced mainly in vehicle exhaust gases, from industrial byproducts, and in fuel combustion, is a toxic compound with a pungent odor that is harmful to the environment, being a major cause of acid rain and photochemical smog. the reactions of NO2 gas with moisture, ammonia, hydrocarbons, and other compounds generate minute particles, which can cause inflammation of the airways in human beings. In response to this increasing risk to health and to minimize the effects of prolonged NO2 inhalation, almost all countries have established regulatory and legislative standards to deal with this issue. For example, the European Commission suggests an hourly exposure to NO2 concentrations of no more than ∼106 ppb no more than 18 times per year. The reactions of NO2 gas with moisture, ammonia, hydrocarbons, and other compounds generate minute particles, which can cause inflammation of the airways in human beings.. The reactions of NO2 gas with moisture, ammonia, hydrocarbons, and other compounds generate minute particles, which can cause inflammation of the airways in human beings.4 In response to this increasing risk to health and to minimize the effects of prolonged NO2 inhalation, almost all countries have established regulatory and legislative standards to deal with this issue.. The European Commission suggests an hourly exposure to NO2 concentrations of no more than ∼106 ppb no more than 18 times per year Exposure levels above this limit result in an increased incidence of acute respiratory illness. Our results have revealed that C3N monolayers are promising candidates for use as gas sensors for NO2 detection and, more interestingly, that C3N monolayers can be used as potential optical gas sensors

MODELS AND METHODS

RESULTS AND DISCUSSION

CONCLUSIONS