Molybdate-based inorganic-organic hybrid disks with a highly ordered layered structure were synthesized via an acid-base reaction of white molybdic acid (MoO 3 $H 2 O) with n-octylamine (C 8 H 17 NH 2 ) in ethanol at room temperature. The thermal treatment of the as-obtained molybdatebased inorganic-organic hybrid disks at 550 C in air led to formation of orthorhombic a-MoO 3 nanoplates. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermal analysis (TG-DTA), Fourier-transform infrared (FT-IR) spectra, Raman spectra, and a laser-diffraction grain-size analyzer were used to characterize the starting materials, the intermediate hybrid precursors and the final a-MoO 3 nanoplates. The XRD, FT-IR and TG-DTA results suggested that the molybdate-based inorganic-organic hybrid compound, with a possible composition of (C 8 H 17 NH 3 ) 2 MoO 4 , was of a highly ordered lamellar structure with an interlayer distance of 2.306(1) nm, and the n-alkyl chains in the interlayer places took a double-layer arrangement with a tilt angle of 51 against the inorganic MoO 6 octahedra layers. The SEM images indicated that the molybdate-based inorganic-organic hybrids took on a well-dispersed disk-like morphology, which differed distinctly from the severely aggregated morphology of their starting MoO 3 $H 2 O powders. During the calcining process, the disk-like morphology of the hybrid compounds was well inherited into the orthorhombic a-MoO 3 nanocrystals, showing a definite plate-like shape. The a-MoO 3 nanoplates obtained were of a single-crystalline structure, with a side-length of 1-2 mm and a thickness of several nanometres, along a thickness direction of [010]. The above a-MoO 3 nanoplates were of a loose aggregating texture and high dispersibility. The chemical sensors derived from the as-obtained a-MoO 3 nanoplates showed an enhanced and selective gas-sensing performance towards ethanol vapors. The a-MoO 3 nanoplate sensors reached a high sensitivity of 44-58 for an 800 ppm ethanol vapor operating at 260-400 C, and their response times were less than 15 s.

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High-energy and high-power Li-ion batteries have been intensively pursued as power sources in electronic vehicles and renewable energy storage systems in smart grids. With this purpose, developing high-performance cathode materials is urgently needed. Here we report an easy and versatile strategy to fabricate high-rate and cycling-stable hierarchical sphered cathode Li(1.2)Ni(0.13)Mn(0.54)Co(0.13)O2, by using an ionic interfusion method. The sphere-shaped hierarchical cathode is assembled with primary nanoplates with enhanced growth of nanocrystal planes in favor of Li(+) intercalation/deintercalation, such as (010), (100), and (110) planes. This material with such unique structural features exhibits outstanding rate capability, cyclability, and high discharge capacities, achieving around 70% (175 mAh g(-1)) of the capacity at 0.1 C rate within about 2.1 min of ultrafast charging. Such cathode is feasible to construct high-energy and high-power Li-ion batteries.

Chemical sensors based on semiconducting metal oxide nanocrystals are of academic and practical significance in industrial processing and environment-related applications. Novel alcohol response sensors using two-dimensional WO(3) nanoplates as active elements have been investigated in this paper. Single-crystalline WO(3) nanoplates were synthesized through a topochemical approach on the basis of intercalation chemistry (Chen et al 2008 Small 4 1813). The as-obtained WO(3) nanoplate pastes were coated on the surface of an Al(2)O(3) ceramic microtube with four Pt electrodes to measure their alcohol-sensing properties. The results show that the WO(3) nanoplate sensors are highly sensitive to alcohols (e.g., methanol, ethanol, isopropanol and butanol) at moderate operating temperatures (260-360 degrees C). For butanol, the WO(3) nanoplate sensors have a sensitivity of 31 at 2 ppm and 161 at 100 ppm, operating at 300 degrees C. For other alcohols, WO(3) nanoplate sensors also show high sensitivities: 33 for methanol at 300 ppm, 70 for ethanol at 200 ppm, and 75 for isopropanol at 200 ppm. The response and recovery times of the WO(3) nanoplate sensors are less than 15 s for all the test alcohols. A good linear relationship between the sensitivity and alcohol concentrations has been observed in the range of 2-300 ppm, whereas the WO(3) nanoparticle sensors have not shown such a linear relationship. The sensitivities of the WO(3) nanoplate sensors decrease and their response times become short when the operating temperatures increase. The enhanced alcohol-sensing performance could be attributed to the ultrathin platelike morphology, the high crystallinity and the loosely assembling structure of the WO(3) nanoplates, due to the advantages of the effective adsorption and rapid diffusion of the alcohol molecules.

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