Adsorption of SF6Decomposition Components on Pt-Doped Graphyne Monolayer: A DFT Study

Yingang Gui,Zhuyu Ding,Lingna Xu,Chao Tang,Xin He

doi:10.1109/access.2019.2938064

Abstract

To propose a novel type of sensing material applied in the field of sulfur hexafluoride (SF6) insulated gas, we investigated the adsorption performance of SF6 decomposed species (H2S, SO2, and SOF2) on Pt-doped graphyne (GD) monolayer. We initially studied the possible stable structure of Pt–GD monolayer and found that the Pt dopant preferred adsorption onto the $\text{C}\equiv \text{C}$ bond. We further investigated electronic differential density, band structure, and density of states to evaluate the chemical and physical interactions between Pt–GD and four typical gases, namely, H2S, SO2, SOF2, and SF6. The results indicated that only H2S, SO2, and SOF2 molecules were adsorbed onto the Pt–GD with strong chemical interactions due to the large adsorption energy, evident electronic differential density change, and orbital hybridization. These results showed that the strong interactions were caused by the Pt dopant. The conductivity of monolayer was enhanced by H2S but was weakened by SO2 and SOF2. The adsorption capacity occurred in the following order: SO2 > H2S > SOF2 > SF6. Our work determined the stable Pt doping structure on GD and provided theoretical support for a novel material realizing the operation state evaluation of SF6 insulated gas equipment.

Highlights

Sulfur hexafluoride (SF6) gas is widely used in highvoltage power equipment, such as gas-insulated switchgear, gas-insulated breaker, and gas-insulated metal enclosed transmission line on account of its excellent insulation performance, arc extinguishing performance, and stable chemical properties [1], [2]
Considering the excellent gas adsorption and sensing properties of metal-modified GD [26]–[28], this work investigated the adsorption and sensing mechanism of Pt-doped GD monolayer upon SF6 and its decomposition products (H2S, SO2, SOF2) by determining the total density of states (TDOS), partial density of states (PDOS), band structure, and adsorption energy data based on the density functional theory (DFT) calculations [29]
Binding energy was −1.67 eV in the structures shown in Fig. 1(d), (e), (g), and (h) but was −1.55 eV in those presented in Fig. 1(c) and (f), indicating instability because of the less energy released compared with that of the structures in Fig. 1(d), (e), (g), and (h) during the doping procedure

Summary

INTRODUCTION

Sulfur hexafluoride (SF6) gas is widely used in highvoltage power equipment, such as gas-insulated switchgear, gas-insulated breaker, and gas-insulated metal enclosed transmission line on account of its excellent insulation performance, arc extinguishing performance, and stable chemical properties [1], [2]. Gas impurity deteriorates the insulation property of SF6, and a gas sensor is an efficient means to ensure equipment operation by monitoring decomposition products [7]. When the adsorption of HCN on the pristine and Si-doped GD is compared, the GD monolayer shows increased sensitive to HCN gas after Si atom doping [25]. Considering the excellent gas adsorption and sensing properties of metal-modified GD [26]–[28], this work investigated the adsorption and sensing mechanism of Pt-doped GD monolayer upon SF6 and its decomposition products (H2S, SO2, SOF2) by determining the total density of states (TDOS), partial density of states (PDOS), band structure, and adsorption energy data based on the density functional theory (DFT) calculations [29]

COMPUTATION DETAILS

RESULTS AND DISCUSSION

CONCLUSION