Structured Graphene Oxide/Reduced Graphene Oxide Interfaces for Improved NO₂ Sensing

Abstract

Here, we demonstrate an improvement in sensitivity toward the NO2 analyte by varying the width ratio of adjacent graphene oxide (GO) and reduced graphene oxide (rGO) layers using the GO laser reduction technique. We evaluated changes brought by laser reduction in material morphology, structure, electrical characteristics, and sensing performance depending on the GO/rGO ratio, which we supported by density functional theory calculations. Our results indicate that the reduction of GO yields the appearance of a chemiresistive response to NO2. An optimum GO/rGO width ratio ensures high conductivity paired with good sorption capacity, allowing to achieve chemiresistive response of 18.1% toward 100 ppm of NO2 at 25 ± 1 °C and a limit of detection of 230 ppb. The improved chemiresistive response of GO/rGO sensors upon NO2 physisorption is due to an increase in sorption energy and improved charge transfer in the presence of NO2 at the sites corresponding to the individual epoxy and hydroxyl groups at the GO/rGO interface area when compared to fully reduced GO.

Transition metal (Ti, Cu, Zn, Pt) single-atom modified graphene/AS2 (A = Mo, W) van der Waals heterostructures for removing airborne pollutants

“…The electronic properties calculations indicate that a well-defined pattern may appear when detecting the molecules, so the systems can be considered good pollutant molecule sensors. Reports can be found about gas sensors with an ultralow detection limit, 75 where the sensitivity and selectivity depend on the surface functionalization, such as epoxy or hydroxyl groups in graphene oxide, 76 doping, and decoration that change transport properties. show the structural and electronic properties of the graphene single-atom catalyst (GSAC) on the MoS 2 (GSAC/MoS 2 ).…”

Magnetic Chemiresistive Fe-Doped In2O3 Nanocubes to Tunably Detect NO2 at ppm to ppb Concentrations

“…Combustion of fuel produces highly corrosive and acidic NO 2 gas which directly harms the human respiratory tract and increases severe respiratory infections and asthma. − It is also known that long-term exposure to high ppm of NO 2 leads to chronic lung disease. − NO 2 can be detected selectively by a chemiresistive method. Various techniques have been applied to enhance the NO 2 sensing response of chemiresistive materials. ,− For instance, Gangareddy et al recently introduced Au nano island embedded H-glass as an effective NO 2 sensor, where the exposed surface area of Au nano islands and local field effectively improved the NO 2 response . Cha and co-workers obtained noteworthy enhancement in low ppm of NO 2 response of 2D WS 2 edge functionalized multichannel carbon nanofibers due to the synergistic effect of increased surface area and porosity .…”

“…Cha and co-workers obtained noteworthy enhancement in low ppm of NO 2 response of 2D WS 2 edge functionalized multichannel carbon nanofibers due to the synergistic effect of increased surface area and porosity . Kumar et al have shown improved NO 2 sensing by increasing NO 2 physisorption by increasing the width of the GO/rGO interface . Li et al synthesized flower-like SnSe 2 /SnO 2 and showed enhanced NO 2 sensing under UV radiation .…”