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Hierarchical 3D flower-like MoS 2 nanospheres with the diameter of about 300 nm were successfully synthesized via a facile hydrothermal process assisted with CTAB. And we found that CTAB played a vital role on the formation of MoS 2 architectures. As the concentration of CTAB increasing, MoS 2 nanopowders with sheet-like, flower-like, large size spherical morphologies were synthesized. And particle sizes of synthesized powders also increased. The optimum concentration of CTAB for the well-defined 3D hierarchical spherical morphology of MoS 2 was 6 g/L. In addition, a feasible formation mechanism of the morphology evolution was put forward in detail on the basis of the experimental results. The gas–sensing properties of flower-like MoS 2 nanospheres were tested. The result indicated that the sensor exhibited high response and selectivity towards NO 2, which may be related to the open and well-defined structures and the abundant micro reaction rooms assembled by ultrathin nanosheets. [ABSTRACT FROM AUTHOR]

A facile hydrothermal route was developed for the preparation of well-aligned hierarchical flower-like NiO nanostructure with the assistance of SDS that served as a structure-directing agent as well as a capping agent in the process of aggregation and assembly. Notably, the NiO sensors exhibit enhanced gas-sensing performance towards ethanol, which could be explained in association with the ultrathin nanosheets that are close to Debye length (L D ) scale and thus get the majority carriers fully depleted due to the ionization of adsorbed oxygen, abundant effective gas diffusion paths as well as high surface-to-volume ratio to promote sufficient contact and reaction between the NiO sample and ethanol molecules, and numerous miniature reaction rooms assembled with nanosheets to make the test gas molecules stay long enough for completed gas-sensing reactions. Besides, a novel growth mechanism with the passage of reaction time was also proposed in detail. [ABSTRACT FROM AUTHOR]

ZnO nanoparticles, nanoplates and nanoflowers have been successfully synthesized via a facile hydrothermal route, and their microstructures and gas-sensing properties to ethanol were investigated. Among all the nanostructures, the nanoplates-assembled nanoflowers exhibited significantly higher gas-sensing performances than the others, which may ascribe to their hierarchical architectures with large specific area and abundant spaces for gas diffusion. Furthermore, we surprisingly found that the concentration of surfactant CTAB used had an essential effect on the ultimate morphology of the hierarchical nanoflowers. We hoped our findings could be in favor of further investigations on the fabrication of perfect hierarchical architectures. [ABSTRACT FROM AUTHOR]

Urchin-like α-MnO 2 nanostructures were successfully synthesized via a simple hydrothermal process at different synthesis temperatures without using any template or surfactant. The microstructure and morphology of as-synthesized products were systematically investigated by focused ion beam, transmission electron microscopy, and high-resolution transmission electron microscopy. The electrochemical test of the prepared MnO 2 exhibits ideal cyclic voltammetry behavior, high specific capacitance (151.5 F g −1 at a current density of 1 A g −1 ) and excellent cycling stability (93.4% capacitance retention after 1000 cycles) which suggests its promising application as supercapacitor. [ABSTRACT FROM AUTHOR]