title: Bundled tungsten oxide nanowires under thermal processing.
abstract: Ultra-thin W(18)O(49) nanowires were initially obtained by a simple solvothermal method using tungsten chloride and cyclohexanol as precursors. Thermal processing of the resulting bundled nanowires has been carried out in air in a tube furnace. The morphology and phase transformation behavior of the as-synthesized nanowires as a function of annealing temperature have been characterized by x-ray diffraction and electron microscopy. The nanostructured bundles underwent a series of morphological evolution with increased annealing temperature, becoming straighter, larger in diameter, and smaller in aspect ratio, eventually becoming irregular particles with size up to 5 µm. At 500 °C, the monoclinic W(18)O(49) was completely transformed to monoclinic WO(3) phase, which remains stable at high processing temperature. After thermal processing at 400 °C and 450 °C, the specific surface areas of the resulting nanowires dropped to 110 m(2) g(-1) and 66 m(2) g(-1) respectively, compared with that of 151 m(2) g(-1) for the as-prepared sample. This study may shed light on the understanding of the geometrical and structural evolution occurring in nanowires whose working environment may involve severe temperature variations.
authors.affiliation: Nanotubes Laboratory, Advanced Materials Research Group, School of Mechanical, Materials and Manufacturing Engineering, The University of Nottingham, Nottingham NG7 2RD, UK. Research Center of Advanced Materials, School of Materials Science and Engineering, Shandong University, Shandong, Jinan 250061, People's Republic of China.
authors.forename: Shibin
authors.initials: S
authors.lastname: Sun
authors.forename: Yimin
authors.initials: Y
authors.lastname: Zhao
authors.forename: Yongde
authors.initials: Y
authors.lastname: Xia
authors.forename: Zengda
authors.initials: Z
authors.lastname: Zou
authors.forename: Guanghui
authors.initials: G
authors.lastname: Min
authors.forename: Yanqiu
authors.initials: Y
authors.lastname: Zhu