Plate-like Cr 2 O 3 has been proved to be highly selective in sensing of nitric oxide (NO), while the sensing response of irregular shape and cubic-like Cr 2 O 3 toward NO was significantly interfered by hydrocarbons (HCs), e.g. C 3 H 6 . In this paper, sensing mechanism of the plate-like Cr 2 O 3 for selective sensing of NO (against HCs) was studied via crystallographic phase analysis, lattice fringes investigation and evaluation of the catalytic activity (gas-phase catalytic activity & electrochemical catalytic activity). The Cr 2 O 3 samples with plate-like, irregular shape and cubic-like microstructures have been confirmed to be the same crystallographic phase through XRD measurements, however, significant difference in the lattice fringes of these Cr 2 O 3 samples were observed via high-resolution transmission electron microscopy (HRTEM) & selected-area electron diffraction (SAED). The comparison results of catalytic activity for plate-like, irregular shape and cubic-like Cr 2 O 3 indicated that the unique selectivity for the plate-like Cr 2 O 3 was mainly caused by the electrochemical reaction specifically toward NO, which occurred near the interface between plate-like Cr 2 O 3 and zirconia-based electrolyte.
CS- x ( x = 1, 2, 4, 6) nanoparticles have been successfully prepared by simple hydrothermal method combined with calcination process, and the calcination time is adjusted to optimize micro-structure characterization for their enhanced NO-sensing. The techniques of XRD, Raman, SEM, TEM, TGA, DSC, BET, and XPS are used to study their phase structure, micro-morphology, thermal decomposition process and surface states, then the possible gas-sensitive mechanism is analyzed. Results show that the typical CS-2 sensor has the maximum response of 130–50 ppm NO at 90 ℃, the short response/recovery time of 40/45 s, and the low detection limit of 0.1 ppm (1.18). It also has the reliable NO selectivity against to other interfering gases, good repeatability and high stability. Its enhanced NO-sensing performance may be due to the optimization of pore structure by adjusting the calcination process based on particles adhesion and mass transfer, which increases the pore size and specific surface area that could provide the channel and active sites for gas diffusion and adsorption, thus further promoting the gas-sensing reaction. The experimental methods and ideas of pore structure regulation provide a new way for the design of high-performance sensitive materials.
Xiang Jincheng,Zhang Zhengxin,Li Xiang,Yang Li,Guo Shenghui,Xia Yi
The detection of nitrogen dioxide (NO₂) at room temperature is crucial for environmental monitoring and public health, but achieving high sensitivity and selectivity remains a challenge. In this study, we developed an In₂O₃/MoS₂ gas sensor via the electrostatic self-assembly method for NO₂ sensing. Owing to the addition of MoS 2 , the composite sensitive materials obtained an increased the specific surface area and improved charge transfer ability. Therefore, the In₂O₃/MoS₂ compsites exhibited enhanced NO₂ sensing performance compared to the pure In₂O₃ nanoparticles.
危险品化学品经营许可证（带存储）