Nitrogen Dioxide-Sensing Properties at Room Temperature of Metal Oxide-Modified Graphene Composite via One-Step Hydrothermal Method

Investigation of Microstructure Effect on NO2 Sensors Based on SnO2 Nanoparticles/Reduced Graphene Oxide Hybrids

“…Generally, the NO 2 sensing mechanism for metal oxide NP-modified RGO hybrids could be summarized by the combined action of metal oxide NPs and RGO, where metal oxide NPs act as active centers for boosting gas sensing properties, meanwhile, the excellent carrier transfer rate of RGO ensures the achievement of constructing the RT sensor. , As discussed in the sensing behavior of metal oxide composites, outstanding RT gas sensing performances are highly dependent on the microstructures of metal oxide NP-modified RGO hybrids. , Although the accurate analysis of all the effective factors is still a complicated problem in the present time, the major factors could be concluded as the following aspects: particle size, surface structure, and interface between metal oxide microstructures of such RGO-based sensitive materials are significantly dependent on the synthesis methods or the synthetic conditions. As expected, excellent gas sensing properties can be obtained via controlling the microstructures of hybrids through optimizing synthesis techniques.…”

Acetylene Gas-Sensing Properties of Layer-by-Layer Self-Assembled Ag-Decorated Tin Dioxide/Graphene Nanocomposite Film

“…Apart from the characteristic peaks attributed to SnO 2 , the XRD spectrum of the Ag–SnO 2 /rGO nanocomposite exhibited distinct peaks at 38.10°, 44.37° and 64.17°, which indexed to the (111), (200) and (220) planes of Ag crystallines, respectively [ 33 ]. However, the broad peak of rGO is not obvious in the XRD pattern of the Ag–SnO 2 /rGO nanocomposite, probably because the weak peak of rGO is swamped by the high intensity peak of the SnO 2 at the 2 θ angle of 26.41° [ 34 , 35 ]. Figure 3 d shows the Raman spectrum of the SnO 2 /rGO and Ag–SnO 2 /rGO nanocomposites.…”

“…Figure 12 a shows a schematic of an energy band diagram of the SnO 2 /rGO heterojunction. The band-gaps for n-type SnO 2 and p-type rGO are 3.6 and 0.4 eV, respectively [ 34 ] and their work functions are 4.5 and 5.1 eV for SnO 2 and rGO, respectively [ 40 , 41 ]. Because the Fermi energies are not at the same level and the rGO has a higher work function, when SnO 2 and rGO come into contact with each other, electrons transfer from SnO 2 to rGO, and holes flow in the opposite direction until a dynamic equilibrium state is reached, and thus a depletion layer is formed at the interface [ 42 ].…”

Metal oxide nanomaterial-based sensors for monitoring environmental NO2and its impact on the plant ecosystem: a review

“…The Fermi energy of rGO is higher than that of SnO 2 , so electrons can be transported to SnO 2 from rGO, which can improve the adsorption of NO 2 molecules, resulting in enhanced gassensing performance. 122 A chemically prepared SnO 2 -CuO/rGO ternary compositebased sensor showed 8-15 times higher sensing response than those of CuO/rGO towards 50 ppm NO 2 . It was observed that the SnO 2 -CuO/rGO ternary composite showed a low limit of detection (150 ppb), good selectivity, and long-term stability.…”

“…This may be due to the formation of p-n heterojunction at the interface between the rGO and SnO 2 . The Fermi energy of rGO is higher than that of SnO 2 , so electrons can be transported to SnO 2 from rGO, which can improve the adsorption of NO 2 molecules, resulting in enhanced gassensing performance [122]. NO 2 detection.…”