Bismuth vanadate (BiVO(4)) nanosheets have been hydrothermally synthesized in the presence of sodium dodecyl benzene sulfonate (SDBS) as a morphology-directing template. The nanosheets were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) equipped with an X-ray energy dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), IR spectroscopy, transmission electron microscopy (TEM), and high-resolution TEM (HR-TEM). The BiVO(4) nanosheets had a monoclinic structure, were ca. 10-40 nm thick, and showed a preferred (010) surface orientation. The formation mechanism and the effects of reaction temperature and time on the products were investigated. UV-visible diffuse reflection spectra indicated that the BiVO(4) nanosheets had outstanding spectral selectivity and improved color properties compared with the corresponding bulk materials. Furthermore, the nanosheets showed good visible photocatalytic activities as determined by degradation of N,N,N',N'-tetraethylated rhodamine (RB) under solar irradiation.

Layered double hydroxides (LDHs) are currently attracting intense research interest for their various applications. Three LDH hollow nano-polyhedra are synthesized with zeolitic imidazolate framework-67 (ZIF-67) nanocrystals as the templates. The nanocages well inherit the rhombic dodecahedral shape of the ZIF-67 templates, and the shell is composed of nanosheets assembled with an edge-to-face stacking. This is the first synthesis of the LDH non-spherical structures. And the mechanism of utilizing metal-organic framework (MOF) nanocrystals as templates is explored. Control of the simultaneous reactions, the precipitation of the shells and the template etching, is extremely crucial to the preparation of the perfect nanocages. And the Ni-Co LDH nanocages exhibit superior pseudocapacitance property due to their novel hierarchical and submicroscopic structures.

γ-Fe 2 O 3 nanoplates were prepared by a simple solution process and could be transformed to Fe 3 O 4 nanoplates while keeping the size and morphology unchanged after reduction in hydrazine solution. The crystal structure and surface organic groups of the nanoplates were characterized in detail. The nanoplates exhibited good dispersibility in polar solvents except water and strong dipolar interactions, which favored the formation of one-dimensional chainlike structure. The poly(vinylpyrrolidone) molecules in this system played a key role for the growth of nanoplates, and it was supposed that the formation of nanoplates was a kinetically controlled process. The γ-Fe 2 O 3 and Fe 3 O 4 nanoplates with strong dipolar interactions are ferromagnetic at room temperature.

Nanostructured materials have attracted much attention because of their unique properties and potential applications in many fields. [1] In the last decade, significant progress in the synthesis of nanostructured materials with controlled size and morphology has been achieved. [2,3] One-, two-, or three-dimensional (1D, 2D, 3D) suprastructures assembled from preformed nanoparticles, [4] nanorods/wires and nanotube arrays, [5] nanostructured hollow spheres, [6] and mesostructured semiconductors have been successfully prepared. [7] In past research, amphiphilic molecules have usually been used either to direct nanoparticle aggregation or to form self-assemblies as templates for the fabrication of inorganic nanostructures. When self-assemblies of amphiphilic molecules are used as templates, the products are structurally and morphologically diverse because of the noncovalent interactions between the template molecules, such as hydrogen bonds, electrostatic interactions, van der Waals forces, and hydrophobic interactions, which lead to diverse inorganic nanostructures. [8][9][10] Using amphiphilic molecule assemblies such as vesicles, [11] microemulsions, [12] micelles, [13] and others [14,15] as templates, a variety of hollow inorganic nanostructures, which are usually spherical, have been prepared. In this paper, cubelike Co 3 O 4 nanoboxes, whose walls are constructed of a single layer of nanocrystals, are introduced. To the best of our knowledge, the only previously observed nanoboxes were constructed of noble metals and alloys, and most recently octahedral Cu 2 O nanocages with single crystalline walls have been generated. [16] Our synthesis is based on surfactant particles formed in alcohol solution and the fabrication of Co 3 O 4 nanoboxes using the separately dispersed cubelike particles as templates, which may provide a simple route to the synthesis of metal oxide nanoboxes. As an important magnetic p-type semiconductor, the spinel Co 3 O 4 has extensive applications in, for example, heterogeneous catalysis, solid-state sensors, electrochromic devices, solar energy absorbers, and as anode materials in Li-ion rechargeable batteries. Nanostructured Co 3 O 4 , including films, tubes, fibers, rods, nanocubes, and nanoaggregates, have been prepared to modify or promote its intrinsic properties.[17] Nanoboxes whose walls are constructed of Co 3 O 4 nanocrystals may have unique and interesting properties. The nanoboxes were obtained after the dispersion of Co(NO 3 ) 2 ·6H 2 O and sodium dodecylbenzenesulfonate (SDBS) in absolute ethanol was heated at 90°C for 8 h and then at 180°C for 3 h, followed by removal of the organics. The X-ray diffraction (XRD) pattern of the product indicates the spinel Co 3 O 4 nature (see Supporting Information, Fig. S1). It is estimated from the transmission electron microscopy (TEM) images that ca. 80% of the products are nanoboxes and the remainder is irregularly aggregated Co 3 O 4 particles. The walls of the nanoboxes are composed of small nanocrystals, and the length of the nanobo...

Monodispersed 5-nm Co3O4 nanocrystals are prepared by thermal decomposition, in long carbon chain alcohols, of the intermediate product Co(NO3)2·7C6H13OH, which is first obtained through the reaction of Co(NO3)2·6H2O with n-hexanol. A designed addition of water into the reaction system causes an oriented aggregation of the primary nanocrystals resulting in spherical mesoporous-like nanostructures from tens to several hundred nanometers. IR, XRD, UV−visible, and 1H NMR analysis techniques are applied to determine the intermediate product, and the thermal-decomposition mechanism is identified through gas chromatography-mass spectrum analysis. XRD, TEM, HRTEM, SAED, and TG/MS are used to characterize the oriented aggregating nanostructures. The binder effect of water molecules on the oriented aggregation of the building blocks and the capping effect of the alcohols on the particle surface during the process are discussed.