Synthesis and Characterization of SnO₂-CoO/carbon-coated CoO Core/shell Nanowire Composites

<TEX>SnO₂-CoO</TEX>/carbon-coated CoO core/shell nanowire composites were synthesized by using electrospinning and hydrothermal methods. In order to obtain <TEX>SnO₂-CoO</TEX>/carbon-coated CoO core/shell nanowire composites, <TEX>SnO₂-Co₃O₄</TEX> nanowire composites and <TEX>SnO₂-Co₃O₄</TEX>/polygonal <TEX>Co₃O₄</TEX> core/shell nanowire composites are also synthesized. To demonstrate their structural, chemical bonding, and morphological properties, field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy were carried out. These results indicated that the morphologies and structures of the samples were changed from <TEX>SnO₂-Co₃O₄</TEX> nanowires having cylindrical structures to <TEX>SnO₂-Co₃O₄/Co₃O₄</TEX> core/shell nanowires having polygonal structures after a hydrothermal process. At last, <TEX>SnO₂-CoO</TEX>/carbon-coated CoO core/shell nanowire composites having irregular and high surface area are formed after carbon coating using a polypyrrole (PPy). Also, there occur phases transformation of cobalt phases from <TEX>Co₃O₄</TEX> to CoO during carbon coating using a PPy under a argon atmosphere.