High Sensitivity and Selectivity of AsP Sensor in Detecting SF6 Decomposition Gases

Wang Jin,Chen Dunjun,Lu Hai,Lei Jianming,Yang Guofeng,Xue Junjun,Cai Qing,Zhang Rong,Zheng Youdou

doi:10.1038/s41598-018-30643-y

Abstract

The sensing properties of monolayer arsenic phosphorus (AsP) for the adsorption of SF6, H2O, O2, and SF6 decomposition gases (SO2 and H2S) are theoretically investigated by the first-principle calculations. We calculate the adsorption energy, equilibrium distance, Mulliken charge transfer, and electron localization function (ELF) to explore whether AsP is suitable for detecting SF6 decomposition gases. By comparing the adsorption performance of SF6, H2O, O2, and H2S gases, we have revealed that the SO2 gas molecules could form stable chemisorption with AsP monolayer. The results demonstrate that AsP is highly sensitive and selective to SO2 gas molecules with robust adsorption energy and apparent charge transfer. Furthermore, the current-voltage (I–V) curves reveal that only the adsorption of SO2 can largely modify the resistance of AsP. Our results show that gas sensors based on AsP monolayer could be better than that of black phosphorene (BP) to diagnose the state of online gas-insulated switchgear (GIS).

Highlights

Sulfur hexafluoride (SF6) is widely used in gas-insulated switchgear (GIS) due to its excellent thermal conductivity, high dielectric strength, arc-extinguishing properties, and chemical inertness[1,2]
The adsorption energy of H2S on Arsenic phosphorus (AsP) is significantly smaller than the others, indicating that the AsP monolayer is not suitable for sensing this molecule
The results demonstrate that SF6, H2S, H2O, and O2 gas molecules show physical adsorption on AsP monolayer, while AsP monolayer strongly adsorb SO2 molecules via robust chemical bonds

Summary

Introduction

Sulfur hexafluoride (SF6) is widely used in gas-insulated switchgear (GIS) due to its excellent thermal conductivity, high dielectric strength, arc-extinguishing properties, and chemical inertness[1,2]. The internal insulation defects and aging in GIS equipment may cause partial discharge, which will decompose SF6 into SO2, H2S, and other decomposition products[4,5]. The sensing methods for SF6 decomposition gases include gas chromatography, mass spectrometry, infrared (IR) spectroscopy, ion mobility spectrometry, and metal oxides sensors and so on[6,7,8]. These methods are not suitable for online detection because most of them require sophisticated instruments, well-trained operators, or special operating environment. We firstly investigate the sensing performances of AsP for detecting the main decomposition gases of SF6 (SO2 and H2S) with consideration of the background gas (SF6, H2O, and O2) by using First-Principles

Methods

Results

Discussion

Conclusion