Effect of GNWs/NiO-WO3/GNWs Heterostructure for NO2 Gas Sensing at Room Temperature

Abstract

Recently, as air pollution and particulate matter worsen, the importance of a platform that can monitor the air environment is emerging. Especially, among air pollutants, nitrogen dioxide (NO2) is a toxic gas that can not only generate secondary particulate matter, but can also derive numerous toxic gases. To detect such NO2 gas at low concentration, we fabricated a GNWs/NiO-WO3/GNWs heterostructure-based gas sensor using microwave plasma-enhanced chemical vapor deposition (MPECVD) and sputter, and we confirmed the NO2 detection characteristics between 10 and 50 ppm at room temperature. The morphology and carbon lattice characteristics of the sensing layer were investigated using field emission scanning electron microscopy (FESEM) and Raman spectroscopy. In the gas detection measurement, the resistance negative change according to the NO2 gas concentration was recorded. Moreover, it reacted even at low concentrations such as 5–7 ppm, and showed excellent recovery characteristics of more than 98%. Furthermore, it also showed a change in which the reactivity decreased with respect to humidity of 33% and 66%.

Recent advancements in nano sensors for air and water pollution control

“…However, the active layer of the CTAB functionalized SWCNTs sensor was not that stable in the range of 10-30 ppm, compared to COOH-SWCNTs (Table 1). ZnO/CuO@graphene NH 3 Jagannathan et al 30 GNWs/NiO-WO 3 /GNWs NO 2 Kwon et al 31 Pt-COFs@SnO 2 @carbon nanospheres Triethylamine Shao et al 32 (Ag)-decorated laser-induced graphene (LIG) foam (Ag/LIG) NO 2 Yang et al 33 Mousavi et al, 34 reported using MIL-101(Cr), a highly porous metal-organic framework (MOF), for fabrication of resistive gas sensor for detection of low concentration volatile organic compounds (VOCs). The authors synthesized MIL-101(Cr)/CNT nanocomposite for sensing of methanol, ethanol, formaldehyde, isopropanol, acetone, tetrahydrofuran, acetonitrile, dichloromethane, and n-hexane at room temperature.…”

Construction of Cu2O@Cu1.75S Core‐shell Octahedrons for Enhanced NO2Gas Sensing at Low Temperature

“…The response value of the sample to 60 ppm NO 2 is as high as 33.6, which is superior than those from most of the reported Cu 2 O-based NO 2 gas sensing materials [9-12, 27, 28], as summarized in Table 1. Moreover, NO 2 gas sensing performances of the recently reported p-type metal oxides [29][30][31][32][33][34] have also been summarized in Table S1. By comparison, the gas sensing performance of Cu 2 O@Cu 1.75 S to NO 2 is comparable to those of the recently reported p-type metal oxides.…”

Carbon nanowall-based gas sensors for carbon dioxide gas detection

“…Over the past 10-15 years, many gas sensing devices based on CNWs have been developed for detection of oxygen, nitrogen dioxide, carbon monoxide, ammonia, volatile organic vapors, hydrogen, etc [12,27,[54][55][56][57]. For instance, Kwon et al reported a resistive change-based CNWs/SiO 2 /Si gas sensor for RT detection of toxic gases such as ammonia (NH 3 ) and nitrogen dioxide (NO 2 ) [27].…”