Syntheisis And Properties Of Cobalt Phosphide Nano-Micron Materials

Cobalt phosphide, as a typical representative of phosphide of Ⅵ-ⅧB group, is an interstitial compound. It possessed special magnetic, optical and electrical properties and catalytic properties owing to their unique structure. Researches have showed that these properties were seriously affected by the size and morphology of the materials. Therefore, the synthesis of cobalt phosphide nano-micron materials with special morphologies have attracted more and more attention and become the hotspots. However, due to the relatively late study on phosphide, there were a few reports about cobalt phosphide nano-micron materials and the regulation of the morphology and size were still a problem. In recent years, since three-dimensional material has both the advantage of low dimension and high specific surface area, the synthesis of cobalt phosphide nanomaterials with special morphology especially the three-dimensional morphology was difficult but necessary, and became an important step of the application techniques of phosphide nano-micron materials. In the present paper, some three-dimensional cobalt phosphide nano-micron materials were prepared by solvothermal route, successfully. The formation processes were also proposed corresponding to the morphology obtained at different time. Moreover some possible properties like electrochemical and photocatalytic properties were tested. The details of this paper were as follows:(1) Uniform neatly Co2 P micron flowers were synthesized by a solvothermal route using anhydrous ethanol(Et OH) and water(H2O) as solvent and cetyl trimethyl ammonium bromide(CTAB) as surfactant. It was found that the as-prepared Co2 P had an orthorhombic phase and was composed of a large quantity of well crystallized flowers which were assembled by some taper-shaped nanorods with a length of 1-1.5 μm. The effects of the amount of CTAB, solvent ratio, and reaction time on the formation of Co2 P flowers were also investigated, among which the appropriate amount of CTAB played a key role in the formation of Co2 P flowers by producing free cetyltrimethylammonium(CTA+) cations and adsorbing on some faces of Co2 P crystal. Furthermore, the as-prepared Co2 P flowers as lithium battery cathode material also exhibited the superior electrochemical property. The initial discharge capacity reached 468.4 m A·h/g and remained to be 170 m A·h/g after 100 cycles.(2) Co2 P hollow hierarchical spheres were successfully synthesized by a facile solvothermal route. These hollow microspheres were compound of a large quantity of nanorods with an average length of 300 nm and aspect ratio of 10. Further study showed that the as-prepared Co2 P had an orthorhombic phase and was single crystal. Moreover, the effects of the amount of PEG-10000, reaction temperature and reaction time were also investigated. Wherein, the surfactant PEG-10000 played an important role in the formation of the hollow hierarchical spheres. Based on these experiments, a possible mechanism of the Co2 P hollow hierarchical microspheres was proposed. A test on its photocatalytic degradation effect on the methylene blue showed a degradation rate of 93% after irradiation for 6 h.(3) Three-dimensional(3D) nanoarchitectures with hierarchical structures of nanosheet were successfully prepared via a solvothermal route without any surfactan uising cobalt chloride as cobalt source and the mixed of cyclohexanol and ethylene glycol as solvent. The morphology and phase of the as-prepared samples were characterized by scanning electronmicroscopy and X-ray powder diffraction, respectively. The results showed that the resulting Co2 P samples were pure with an orthorhombic structure and had good crystallinity. A serious experiments showed that the optimal conditions preparing Co2 P 3D nanoarchitectures were that VC6H12O: VEG = 3: 1, the reaction temperature was 210 ℃, reaction time was 16 h. Furthermore, the as-obtained 3D Co2 P nanoarchitectures had a good photocatalytic effect for methyl orange. The degradation rate reached to 65% after irradiation for 3 h.