A DFT study of SO₂ and H₂S gas adsorption on Au-doped single-walled carbon nanotubes

Abstract

Intrinsic carbon nanotubes (CNTs) show limited toxic gas detection, thus, we need to develop a method to fabricate a novel CNT sensor that has good sensitivity. In this study, density functional theory (DFT) was applied to determine the adsorption behavior of Au-doped singlewalled carbon nanotubes (Au-SWCNTs) to SO 2 and H 2 S. The calculated results show that Au-SWCNTs have a high sensitivity to SO 2 and H 2 S. When SO 2 adsorbs on the surface of the nanotube, a large number of electrons transfer from the Au-SWCNT to SO 2 , which results in a decrease in the frontier orbital energy gap and an increase in electrical conductivity. On the other hand, when H 2 S adsorbs on the surface of the nanotube, the electrons transfer from H 2 S to the Au-SWCNT, the frontier orbital energy gap increases, and the electrical conductivity decreases. Thus, SO 2 and H 2 S could be detected by Au-SWCNTs. This conclusion is useful for the development of CNT-based gas sensors and provides a theoretical basis to fabricate Au-SWCNT-based gas sensors.

Electrophoretic deposition of Au NPs on CNT networks for sensitive NO<sub>2</sub> detection

“…Studies (Kim et al, 2007;Pannopard et al, 2009) have indicated that the transition metal has a rich d-electron and empty orbit, and the small gas molecule can bond strongly to the metal when adsorbed on the surface. As previously reported (Kim et al, 2007;Zhang et al, 2014), when metal nanoparticles are deposited on the perfect surface of a nanotube or away from the surface defects, the interaction between the metal and the nanotube is weak; on the other hand, when the metal is adsorbed on the point defect site of the nanotube surface, the structure becomes stable.…”

Comparative Study of Materials to SF6 Decomposition Components

“…To detect, evaluate, and diagnose the insulation status of SF 6 gas insulated equipment using the characteristics of SF 6 decomposition, a series of characteristic SF 6 decomposition components, SOF 2 , SO 2 F 2 , SO 2 , H 2 S, CF 4 , HF, and SF 6 , are detected by gas sensors, including metal functionalized single wall carbon nanotubes (SWCNTs) [1][2][3][4][5][6], TiO 2 nanotubes [7][8][9], and graphene gas sensors [10,11], as shown in Table 1. According to the theoretical calculation results, these three kinds of gas-sensing materials are not sensitive to the background gas SF 6 and decomposition component CF 4 .…”

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]. CNTs have abundant pore structure, large specific surface area, and a strong ability of adsorption and desorption for chemical composition of the gas phase, these properties make CNTs, as gas sensor, incomparable in conventional sensors of the detection sensitivity and miniaturization [20].…”