Adsorption of SF6 decomposed gas on anatase (101) and (001) surfaces with oxygen defect: A density functional theory study

Abstract

The detection of partial discharge by analyzing the components of SF6 gas in gas-insulated switchgears is important to the diagnosis and assessment of the operational state of power equipment. A gas sensor based on anatase TiO2 is used to detect decomposed gases in SF6. In this paper, first-principle density functional theory calculations are adopted to analyze the adsorption of SO2, SOF2, and SO2F2, the primary decomposition by-products of SF6 under partial discharge, on anatase (101) and (001) surfaces. Simulation results show that the perfect anatase (001) surface has a stronger interaction with the three gases than that of anatase (101), and both surfaces are more sensitive and selective to SO2 than to SOF2 and SO2F2. The selection of a defect surface to SO2, SOF2, and SO2F2 differs from that of a perfect surface. This theoretical result is corroborated by the sensing experiment using a TiO2 nanotube array (TNTA) gas sensor. The calculated values are analyzed to explain the results of the Pt-doped TNTA gas sensor sensing experiment. The results imply that the deposited Pt nanoparticles on the surface increase the active sites of the surface and the gas molecules may decompose upon adsorption on the active sites.

Adsorptions of SO2, SOF2, and SO2F2 on Pt-modified anatase (101) surface: Sensing mechanism study

“…on the adsorptions of gas molecules on the TNTA surface, and to derive new methods to improve the sensing property of the TNTA gas sensor. The results basically explain the gas-sensing mechanism of intrinsic TNTA [26,27]. However, considering the conclusions of other scholars at the same time, the sensing mechanism of Pt-modified TNTA still cannot be fully explained [28][29][30][31][32][33][34][35][36][37].…”

“…However, considering the conclusions of other scholars at the same time, the sensing mechanism of Pt-modified TNTA still cannot be fully explained [28][29][30][31][32][33][34][35][36][37]. The preliminary sensing mechanism of Pt-modified TNTA is that the changes of the responses of Pt-modified TNTA to the three gases may be caused by the catalysis of the Pt nanoparticle [27]. The adsorptions of the three gases on the Pt-modified TNTA surface and the higher response of Pt-modified TNTA to SO 2 F 2 in the gassensing experiment than to SOF 2 need further study.…”

Experimental Analysis of Modified CNTs-Based Gas Sensor

“…In recent years, a breakthrough has been making in the sensor technology [16,17]. Especially, the development of nanotechnology has been providing the new material and processing method [18], in which the carbon nanotubes (CNTs) gas sensor has become the new research focus [19].…”

Study on the characteristic decomposition components of air-insulated switchgear cabinet under partial discharge

“…[12][13][14] Currently, various current detection methods: pulse current, ultra-high-frequency electromagnetic wave detection (UHF), transient enclosure voltage (TEV), optoacoustic detection and chemical gas sensor detection methods have been performed to detect the partial discharge according to the physical signals produced along with the partial discharge. [15][16][17][18][19] However, pulse current method is only fit for offline detection, and UHF and TEV method are easily affected by ambient interference signal. These disadvantages make pulse current method, UHF and TEV unsuitable for on-line detection.…”