Room temperature NO₂ sensing: what advantage does the rGO–NiO nanocomposite have over pristine NiO?

Abstract

In recent years, there has been increasing interest in synthesis of reduced graphene oxide (rGO)-metal oxide semiconductor (MOS) nanocomposites for room temperature gas sensing applications. Generally, the sensitivity of a MOS can be obviously enhanced by the incorporation of rGO. However, a lack of knowledge regarding how rGO can enhance gas-sensing performances of MOSs impedes its sensing applications. Herein, in order to get an insight into the sensing mechanism of rGO-MOS nanocomposites and further improve the sensing performances of NiO-based sensors at room temperature, an rGO-NiO nanocomposite was synthesized. Through a comparison study on room temperature NO2 sensing of rGO-NiO and pristine NiO, an inverse gas-sensing behavior in different NO2 concentration ranges was observed and the sensitivity of rGO-NiO was enhanced obviously in the high concentration range (7-60 ppm). Significantly, the stimulating effect of rGO on the recovery rate was confirmed by the sensing characteristics of rGO-NiO that was advantageous for the development of NO2 sensors at room temperature. By comprehending the electronic interactions between the rGO-MOS nanocomposite and the target gas, this work may open up new possibilities for further improvement of graphene-based hybrid materials with even higher sensing performances.

A nickel nanoparticle/carbon quantum dot hybrid as an efficient electrocatalyst for hydrogen evolution under alkaline conditions

“…However, the peak corresponding to C=O shifts slightly, which is due to the formation of Ni−O−C bond. 34 Ultravioletvisible (UV-vis) spectra in Figure S4 illustrates that the hybrid of Ni NPs with CQDs results in an increase in the absorption over the wavelength range from 400 to 800 nm, which may be resulted from the existing Ni−O−C bond and is expected to exhibit enhanced electrocatalytic activity under visible light. High resolution O1s spectrum is displayed in Figure S3b, which reveals the presence of Ni-O-C (530.2 eV), O-H (531.3 eV), C-O (532.2 eV), and C=O (533.5 eV).…”

Synergistic Amplification of Water Oxidation Catalysis on Pt by a Thin-Film Conducting Polymer Composite

“…1s spectrum of the film had peaks at 529.8 eV, 531.8 eV and 533.8 eV. They relate to the binding energy of the Ni-O, C=O and C-O bonds respectively [48][49][50]. Finally, for the Ni spectrum, there were two main peaks due to Ni 2p1/2 and 2p3/2 transitions in the range 848-885 eV(Figure 10(d)).…”

Two‐Dimensional Nanostructured Materials for Gas Sensing

“…Recent reports on graphene/metal oxide nanosheets for gas sensing include a variety of metal oxides such as SnO 2 , ZnO, TiO 2 , WO 3 , Co 3 O 4 , CeO 2 , In 2 O 3, Fe 2 O 3 , NiO . Most of these hybrid nanosheets have been synthesized by wet‐chemical, e.g., hydrothermal or solvothermal methods, providing an easy synthesis, low cost and potential for large‐scale preparation.…”