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Three-dimensional (3D) hierarchical microspheres of Bi12O17Cl2 (BOC) were prepared via a facile solvothermal method using a binary solvent for the photocatalytic degradation of Rhodamine-B (RhB) and Bisphenol-A (BPA). Co3O4 nanoparticles (NPs)-decorated BOC (Co3O4/BOC) heterostructures were synthesized to further enhance their photocatalytic performance. The microstructural, morphological, and compositional characterization showed that the BOC microspheres are composed of thin (~20 nm thick) nanosheets with a 3D hierarchical morphology and a high surface area. Compared to the pure BOC photocatalyst, the 20-Co3O4/BOC heterostructure showed enhanced degradation efficiency of RhB (97.4%) and BPA (88.4%). The radical trapping experiments confirmed that superoxide (•O2−) radicals played a primary role in the photocatalytic degradation of RhB and BPA. The enhanced photocatalytic performances of the hierarchical Co3O4/BOC heterostructure are attributable to the synergetic effects of the highly specific surface area, the extension of light absorption to the more visible light region, and the suppression of photoexcited electron-hole recombination. Our developed nanocomposites are beneficial for the construction of other bismuth-based compounds and their heterostructure for use in high-performance photocatalytic applications. [ABSTRACT FROM AUTHOR]

Morphology transformation and crystal growth strategies of metal oxide semiconductors are still extensively studied in material science recently, because the morphology and crystallinity significantly affect the physicochemical characteristics of metal oxide nanomaterials. However, understanding the morphology changes of α-MoO3 induced by annealing is still a challenge. Herein, the nanostructure transition of α-MoO3 induced by the annealing temperature is carefully investigated via the XRD and SEM methods. It can be found that crystallization is highly dependent on the annealing temperature. Interestingly, the MoO3 nanoflowers can change into nanosheets at 500 °C. Afterward, the nanosheets turned into microrods with the increase in annealing temperature due to the continuous growth of MoO3 crystal. On the other hand, the sensing performances of various MoO3 nanostructures are studied toward ethanol gas. Compared to the MoO3 nanoflowers and microrods, the MoO3 nanosheets-based sensor exhibits superior sensing performance to ethanol, and the maximum response value is 8.06. [ABSTRACT FROM AUTHOR]

Using vanadium oxide (VOx) thin film as active layer, microbolometer with gold black absorber was fabricated due to the high mid-infrared (8-14μm) absorption property of gold black. This paper describes the design and fabrication of microbolometer with micromachining surface technology. The characteristics of the device are investigated. The detector performance exhibits maximum detectivity of 1.96 × 108cmHz1/2/W at 17 Hz with 8.8μA. [ABSTRACT FROM AUTHOR]

Gas sensors based on SnO2, Fe2O3, and their nanocomposites are promising candidates for sensing of acetone, ethanol, hydrogen, NO2, ozone, and formaldehyde. In this work, a rational hydrothermal route is designed to prepare α‐Fe2O3/SnO2 porous sphere arrays assembled with hierarchical nanostructure (denoted as α‐Fe2O3(x%)/SnO2). The results demonstrate that the α‐Fe2O3(4%)/SnO2 based sensor exhibits excellent sensing performance, the short response/recovery time of 3 and 4 s, respectively. A very low working temperature of 200 °C, wide linear detection range (from 500 ppb to 500 ppm), and long‐term cycling stability of as long as 90 days, and stable performance at 80% of relative humidity. The sensing signals can be accurately sampled and processed by the integrated circuit system, to collect and monitor the acetone concentration alteration signals in real time. Furthermore, the gas sensing performance is interpreted by the functions of hierarchical nanostructure and synergistic effect of Fe2O3/SnO2 nanohybrids. [ABSTRACT FROM AUTHOR]

Metal oxide semiconductor sensors based on nanocrystalline In2O3 and its composites are found to be very sensitive in detecting low-concentration (~ 5 ppm) gases such as ozone, nitrogen dioxide, formaldehyde and butane. Here, we successfully obtained fiber-shaped In2O3 crystalline nanofibers via electrospun and calcination routes. The gas sensing properties of the In2O3 nanofibers were studied by exposing them to the acetic acid vapor with different concentrations from 500 ppb to 2000 ppm at the optimum operating temperature (250 °C). The device possesses ultra-high response of 66.7 toward 2000 ppm acetic acid vapor, low response and recovery times of 25 s and 37 s (100 ppm), respectively, and significant selectivity to acetic acid at 100 ppm. In particular, the sensor based on In2O3 nanofibers has very low detection limit and can reach 500 ppb. Therefore, the presented In2O3 nanofiber sensor can be used in practice in acetic acid detection area in the future. [ABSTRACT FROM AUTHOR]

The use of 1-(hydroxymethyl)-3,5-dimethylpyrazole (HL), a functionalized pyrazole ligand, to assemble with CoX2 (X = Cl or Br) in the presence of triethylamine under low-temperature solvothermal conditions gave rise to two tetranuclear cobalt(II) clusters, [Co4L6X2] [X = Cl ( 1), Br ( 2)]. Both CoII4 clusters are isostructural and protected by four µ2- N1: O2 and two µ3- N1: O3L- as well as terminal X anions to form a face-shared open bicubane structural motif. Magnetic susceptibility measurements indicated that there is an intramolecular antiferromagnetic interaction between four CoII atoms in 1 and 2. Although the core motif of 1 and 2 is not classic Co4O4 monocubane, both are active catalysts for water oxidation, and their relative O2-evolution rates are dependent on the halogen terminal ligands, which is also supported by spin-polarized density functional theory (DFT) calculations. Both clusters exhibit semiconductor behavior with σ values on the 10-9 S cm-1 scale at room temperature; however, mechanical iodine doping results in up to an astonishing 105-fold maximum enhancement of solid-state conductivity relative to the undoped samples. This work therefore presents a new core type of cobalt cluster that possesses photocatalytic oxygen-evolution capabilities, provides new insight into the catalysis-related mechanism based on the relative oxygen-evolution efficiency, and applies the iodine-doping strategy to boost the conductivity of cluster compounds. [ABSTRACT FROM AUTHOR]