No abstract

No abstract

No abstract

A novel growth method for CuO-functionalized, branched tin oxide (SnO2) nanowires was developed on the basis of a Cu-triggered tip-growth vapour–liquid–solid (VLS) process during annealing of Cu-coated SnO2 nanowires. The variation in annealing temperature changed the morphology, in which higher temperatures (⩾500 °C) are favourable for the formation of branches. From the observation of tip nanoparticles, we revealed that the growth of branches at 500 and 700 °C was dominated by base-growth and tip-growth VLS processes, respectively. The tip nanoparticles at 700 °C were mainly comprised of a CuO phase. We have demonstrated the potential applicability of the CuO-functionalized, branched SnO2 nanowires to H2S sensors. CuO functionalization significantly enhanced the response to H2S. In sharp contrast, it degraded the response to NO2, suggesting their selective sensing performance to H2S.

We have successfully fabricated single- and few-layer mica nanosheets, by means of using a solvothermal method in conjunction with a microwave irradiated expansion process. In the solvothermal process, dissolved potassium ions were intercalated onto the interlayer space of the mica. Following this, microwave irradiation facilitates the exfoliation of individual nanosheets. The synthesized products were characterized by field emission scanning electron microscopy, transmission electron microscopy (TEM), atomic force microscopy (AFM), x-ray diffraction, x-ray photoelectron spectroscopy (XPS), and Raman spectroscopy measurements. AFM and TEM studies claimed the existence of single-layer mica. High-resolution TEM (HR-TEM) investigations revealed that the exfoliated product corresponded to a crystalline mica structure, being comprised of Si, Al, O, and K elements. XPS spectra exhibited the major constituent peaks, including O 1s, Si 2p, Al 2p, and K 2p. In addition, C atomic concentration has been slightly increased by the contamination during exfoliation, presumably due to the increase of the exposed mica surface. The C 1s XPS spectra revealed that the C-C bonding in organic surface contaminants was broken, whereas the Si-C bonding was enhanced, by the exfoliation process. The O 1s XPS spectra revealed that the Si-O bonding in mica was broken, generating the O-Si-C bonding. This study paves the way towards the fabrication of single- or few-layer inorganic nanosheets of desired materials, via a convenient and efficient route.