Tunable and optimal interlayer spacing of 2D VS2 with high response and fast recovery for NO2 detection

Synergism of Edge Effect and Interlayer Engineering of VS2 on CNFs for Rapid and Precise NO2 Detection

“…As demonstrated in our previous research, 27 the expanded interlayer spacing of VS 2 also played a crucial role in improving its NO 2 sensing response, especially in speeding the τ res /τ rec of sensors. As illustrated in Figure 5(c), more NO 2 molecules have easier access to the wider interlayer, which improves the interaction of VS 2 -E-C3 with NO 2 .…”

“…The NH 4+ intercalation-induced c-axis direction lattice expansion of VS 2 is responsible for the migration of (001) diffraction peaks. 27 Due to the massive offset and high intensity of the (001) peak, the other VS 2 peaks are almost indistinguishable in comparison. 41,42 The Raman spectra of VS 2 -E and VS 2 -E-C are given in Figure 1(c).…”

“…As illustrated in Figure (c), more NO 2 molecules have easier access to the wider interlayer, which improves the interaction of VS 2 -E-C3 with NO 2 . The enlarged interlayer spacing makes it simpler for NO 2 molecules to adsorb/desorb, which can substantially accelerate the diffusion rate of NO 2 within layers, thereby speeding up the response/recovery of the VS 2 -E-C3 sensor . More favorably, the exposure of more active edges in VS 2 means more emergence of the expanded interlayer, enabling more NO 2 molecules to interact with the edges as well as enter the interlayer of VS 2 , and the synergistic effect of both greatly enhanced the NO 2 -sensing properties of VS 2 -E-C3 .…”

“…Owing to the low working temperature, large specific surface area, and sensitive change of carrier concentration on gas molecules, two-dimensional (2D) layered transition-metal dichalcogenides (TMDs) have drawn ever-increasing interest as gas-sensing materials. − NO 2 is one of the most dangerous gases among all toxic and hazardous air pollutions. Excess NO 2 in the atmosphere might cause environmental problems such as acidification deposition and photochemical smog. , Even more, it can induce asthma and other respiratory diseases when the concentration exceeds 1 ppm, posing a serious threat to human health. , VS 2 , as a typical TMDs, has been found to present high potential in the field of gas sensors due to its superior electrical conductivity and the distinctive V atom 3d electron orbital. − In the previous research of our team, , the rapid response/recovery time (10/10 s at 100 °C) to NO 2 was successfully achieved by expanding the interlayer spacing of VS 2 , and the interlayer-sensing mechanism of 2D TMDs was investigated systematically. The enlarged spacing of VS 2 promotes the diffusion rate of NO 2 between interlayers, accelerates their adsorption/desorption, provides more space for interaction of VS 2 with NO 2 , and therefore enhances the response and speed up the response/recovery of VS 2 to NO 2 .…”

“…22,23 VS 2 , as a typical TMDs, has been found to present high potential in the field of gas sensors due to its superior electrical conductivity and the distinctive V atom 3d electron orbital. 24−26 In the previous research of our team, 27,28 expanding the interlayer spacing of VS 2 , and the interlayersensing mechanism of 2D TMDs was investigated systematically. The enlarged spacing of VS 2 promotes the diffusion rate of NO 2 between interlayers, accelerates their adsorption/ desorption, provides more space for interaction of VS 2 with NO 2 , and therefore enhances the response and speed up the response/recovery of VS 2 to NO 2 .…”