Super Stable Pollution Gas Sensor Based on Functionalized 2D Boron Nitride Nanosheet Materials for High Humidity Environments

Abstract

We report on studies of new gas sensing devices to be used in high humidity environments. Highly thermal-stable, super hydrophobic 2-dimensional (2D) boron nitride nanosheets (BNNSs) functionalized with Pt nanoparticles were prepared and used as an active layer for the prototype. The morphologic surface, crystallographic structures and chemical compositions of the synthesized 2D materials were characterized by using optical microscope, scanning electron microscope (SEM), transmission electron microscope (TEM) and atomic force microscope (AFM) and Raman scattering, respectively. The experimental data reveals that high-quality BNNSs were prepared. A pair of Au electrodes were combined with a basic electrical circuit and the 2D sensing material to form high-performance gas sensors for the detection of pollution gases. The present structure is simple and the fabrication is easy and fast, which ensures the creation of a low-cost prototype with harsh (high humidity, high temperature) environment resistance and potential for miniaturization. The responses of the prototype to different target gases with different concentrations were characterized. The influences of the operating temperature and bias voltage effect on sensing performances were also investigated. The fabricated sensors appear to have high selectivity, high sensitivity and fast response to target gases. The sensing mechanism in the present case is attributed to the electron donation from the target gas molecules to the active layer, leading to the change of electrical properties on the surface of BNNS layer.

Chemical Sensing Properties of BaF2-Modified hBN Flakes towards Detection of Volatile Organic Compounds

“…Furthermore, the abundant nitrogen and/or boron vacancies (V N or V B ) in the defective structure of hBN could have acted as electron capture sites upon exposure to either acetone or ethanol [45,46], thereby resulting in improved sensitivity. Interestingly, regardless of the theoretical studies showing that the even, smooth surfaces of hBN nanosheets enabled full access of their atoms to the adsorbing gas molecules, thus allowing for larger sensor area per unit volume and improving the sensitivity [25][26][27], our results showed that the formation of well-defined morphology hBN nanosheets greatly hindered their performance towards the detection of volatile organic compounds. In summary, the results indicated that our synthesised hBN nanosheets are potential candidates for room temperature chemoresistive gas sensors (Table 2), as the obtained values were comparable to those of graphene, conductive metal oxides, mxenes, as well as transition metal dichalcogenides (TMDs) [25].…”

“…Interestingly, regardless of the theoretical studies showing that the even, smooth surfaces of hBN nanosheets enabled full access of their atoms to the adsorbing gas molecules, thus allowing for larger sensor area per unit volume and improving the sensitivity [25][26][27], our results showed that the formation of well-defined morphology hBN nanosheets greatly hindered their performance towards the detection of volatile organic compounds. In summary, the results indicated that our synthesised hBN nanosheets are potential candidates for room temperature chemoresistive gas sensors (Table 2), as the obtained values were comparable to those of graphene, conductive metal oxides, mxenes, as well as transition metal dichalcogenides (TMDs) [25]. Moreover, the sensors were found to be stable even after 18 months of storage as approximately 75%, 50%, 92%, and 8% decreases in sensor responses were observed for 0 wt %, 2.5 wt %, 5 wt %, and 10 wt % modified hBN samples after exposure to 160 ppm of acetone (Figure S7).…”

“…Additionally, hBN nanosheets have good adsorption properties due to the partially ionic B-N chemical bonds and their 2D nature, which subsequently lead to high surface/volume ratio and enable total exposure of their atoms to the adsorbing gas molecules [23,24], thus rendering them excellent candidates as active materials in gas-sensing technology. Theoretically and experimentally, gas-sensing performance of hBN nanosheets was predicted for CH 4 , F 2 , NO 2 , H 2 , N 2 , O 2 , and CO 2 [20,25]. However, to the best of our knowledge, their experimental performance towards VOCs is rather scarce.…”

Theoretical study of 2D PbSe/Bi2Se3 heterojunctions as gas sensors for the detection of SO2 and Cl2

“…2D materials exhibit many peculiar properties, such as tunable band gap [2], controllability of spin degrees of freedom and valley degrees of freedom [3,4], etc. Due to its larger specific surface area, more adsorption sites, excellent electrical conductivity and other advantages, and its synthesis, stability, manufacturing costs and other aspects of continuous optimization and improvement, 2D materials as the representative of the gas sensor will be able to achieve miniaturization, low power consumption and other goals [5][6][7][8]. PbE(E = S, Se, Te) semiconductor nanomaterials of the sulfur genus of lead are characterized by low cost and elemental abundance.…”