Advanced Materials Research Vols. 554-556

Abstract: The reaction between Fe(CO)₄I₂ and Ni(SR)₂(dppe) affords NiI₂(dppe) due to the nucleophilic attack of iodide on the labile Ni-S(thiolate) bonds. The iodide-dithiolate-bridged binuclear Ni-Ni complexes [(dppe)Ni(µ-I)(µ-pdt)Ni(dppe)]I is readily prepared from the reaction between [NiI₂(dppe)] and [Ni(pdt)(dppe)] [dppe = 1,2-bis(diphenyl phosphino)-ethane; pdt = 1,3-propane-dithiolate] in CH₂Cl₂ as a result of attack on Ni-I bond by the lone pairs of electrons on thiolato sulfur donors. The reaction between [FeCp(CO)₂I] and [Ni(pdt)(dppe)] in CH₂Cl₂ processes extremely slowly. However, upon metathesis with NH₄PF₆, the iodide-thiolate bridged binuclear Ni-Ni complexes [(dppe)Ni(µ-I)(µ-pdt)Ni(dppe)]PF₆ is formed from the reaction of iodide and the Ni(II)-S bonds. The reaction between [NiCl₂(dppe)] and NH₄PF₆ and [Ni(pdt)(dppe)] gives a binuclear complex [(dppe)Ni(µ-pdt)Ni(dppe)]PF₆ without a halide-bridge. These results suggest that the reactivity of Ni-SR bonds in the Ni-thiolate-phosphine complexes is tunable with regard to the electronic environment of second metal ion and the different reactivity of iodide moiety. Electrochemical and crystallographic results are also analyzed for relevant compounds.

Abstract: Abstract: Graphite oxide is of great importance in preparing graphene, the average layer of graphene depends on that of graphene oxide in some extent. In this paper, we prepared graphite oxide via H₃PO₄/H₂SO₄ mixed acid, then which were dried by vacuum drying in a freezer dryer and drying oven respectively, the graphite oxide powder and thin film were obtained correspondingly. After dispersing the above two forms of graphite oxide in water by shaking, stirring or supersonic wave, they were reduced in the same condition. According to the XRD, AFM results, vacuum freeze-drying was inclined to gain few-lay graphene.

Abstract: MoS₂ nanoparticles with fullerene-like (IF-MoS2) structure were successfully obtained at heating temperature higher than 840 °C by chemical vapor deposition method in a three-tube furnace using MoO₃ and S (sulfur) powders as raw materials. The synthesized samples were characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, and energy dispersion X-ray spectrometerrespectively. IF-MoS₂ nanoparticles can be obtained only in the narrow temperature range of 840 °C-870 °C, and the diameter of IF-MoS₂ nanoparticles increases with temperature. A gradual formation mechanism of IF-MoS₂ nanoparticles was discussed in detail.

Abstract: Copper sulfide (CuS) nanotubes assembled by nanoparticles were successfully synthesized by reaction thiourea with Cu(OH)₂ nanowire precursor which was obtained using CuCl₂ and NaOH as raw materials in the solvent ethylene glycol at 80 °C by a facile microwave-assisted solvothermal method. The forming influencing factors of CuS nanotubes were investigated. One of the advantages of this method is that the preparation of CuS nanotubes can well duplicate the shape of the nanowire precursor, thus the simplicity and low cost can be achieved. The products are characterized by X-ray powder diffraction (XRD) and transmission electron microscopy (TEM). The photocatalytic property of the CuS samples was also investigated.

Abstract: In this paper, mono-dispersed cerium oxide nano powders have been synthesized via a mixed solvothermal route. The influences of solvents’ compositions and solvothermal temperatures on the crystallization of cerium oxide have been investigated. The results indicated that the formation temperature decreased when the mixed solvent was used and the existences of alcohols played as the reducing agents and delayed the crystallization of cerium oxide, which had great influences on both yield ratios and morphologies of the synthesized nano powders.

Abstract: The hydrogen reduction and water-splitting oxidation for hydrogen storage and release on the iron oxide mediums with Ce, Mo or Ce-Mo additives were carried out using a fixed bed reactor at atmospheric pressure. A sole Ce additive was an outstanding material for the improvement of the reactivity in the reduction and oxidation of iron oxide medium, even though the medium with Ce was easily deactivated during repeated cyclic reactions due to sintering. A sole Mo additive was a good material for the improvement for the durability. In the mediums with the Ce-Mo additives, therefore, the degree of deactivation and the reactivity of the mediums were gradually decreased with the increase of the amount of Mo. Among the iron oxide mediums with Ce-Mo additives, a FeCeMo-5 medium exhibited the good durability while the maintaining the considerable reactivity during the cyclic reactions.

Abstract: In this study, large pore size and highly ordered mesoporous molecular sieve SBA-15 was successfully synthesized in the acidic medium by using n-propanol as the pore-expanding agent, and tetraethyl orthosilicate (TEOS) as silicon source and poly(ethylene oxide)-block-poly(propylene oxide)-block-poly(ethylene oxide) triblock copolymer (P123 triblock copolymer) as a template agent. The samples were characterized by Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM) and Nitrogen Adsorption-Desorption. It is found that the particles of mesoporous molecular sieve SBA-15 have regular morphology and ordered pore structure, and also have high specific surface area, large pore size and pore volume.

Abstract: We prepared graphite oxide (GO) from natural graphite by the modified Hummers method. Then graphene was prepared by ultrasonically dispersing GO in the presence of hydrazine hydrate. The samples were characterized by FTIR, Raman, Scanning electron microscope (SEM) and Transmission electron microscope (TEM). The results suggest that the graphite is oxidized to covalent bond-type graphite intercalation compounds with various oxygen functional groups (C=O, C-OH, -COOH and C-O-C). Results show that the functional groups on graphite oxide surface are mostly removed by hydrazine hydrate and graphene presents translucent slide with curly edge.

Abstract: Cuprous oxide (Cu₂O) nanoparticals with high uniformity were prepared by the hydrothermal synthesis method using copper chloride and potassium chloride in the solvent of distilled water. Their micro- structures were characterized by using XRD, XPS and TEM techniques. The photocatalysis of the prepared samples were evaluated by the degradation of melthyl orange (MO) in aqueous solution under solar light irradiation. It can be found that Cu₂O sample was highly efficient catalysts and the Catalytic degradation of the Cu₂O nanoparticals for MO was not only due to the quality of Cu₂O samples but also to the concentration of H₂O₂. The decoloring ratio for MO solution has reached 98.6% in 110min

Abstract: In this article, a new way to prepare ferrate solution was proposed by combining microwave irradiation and hypochlorite-oxidation method. It was demonstrated that the reactivity speed can be improved as high as 30 times compared to the single hypochlorite -oxidation method.