Uniform LnPO(4).x H(2)O (Ln=Y, La-Nd, Sm-Lu) nanocrystals that have controllable 0D (spherelike), 1D (rodlike), and 2D (polygonlike) structures have been systematically synthesized by means of a hydrothermal method by using a mixed solvent of water and ethanol. Transmission electron microscopy images and SEAD (selected area electron diffraction) patterns revealed that the products are highly crystalline and have structurally uniform shapes. IR, Raman, and electron energy loss spectroscopies gave spectra that indicated that an amount of oleic acid molecules were presented at the surface of individual nanocrystals. These nanocrystals have hydrophobic surfaces and could be easily dispersed in nonpolar solvents. Moreover, a creditable synthetic mechanism for nucleation, growth, and shape evolution has been proposed. Eu(3+) doped products were also prepared by using the same synthetic process. The Eu(3+) doped products exhibited an orange-red luminescence that is ascribed to an electron transition within the 4f shell. Analysis of the photoluminescent spectra revealed that the optical properties are strongly dependent on their morphologies.

Catalysis-the basis of modern chemical industry-plays a vital role in petroleum refining and in applications in medicine, energy, and the environment; therefore, it has high significance for our life. Supported noble-metal catalysts are among the most important catalysts for industrial applications. [1] During the past few decades, extensive research efforts have focused on the effect of particle size of noble metals, the nature of the supporting materials (commonly oxides), and the surface and interfacial effect to improve the performance of these catalysts, and great progress has been achieved. [2][3][4] However, many intractable problems still exist that hinder the development of this field; one of them is the thermal stability of the catalysts. [5] In supported noble-metal catalysts the metal particles tend to aggregate during the reaction process, and the particle size thus becomes larger which leads to lower catalytic activity. Additionally, the metal particles usually detach from the support when the corresponding catalyst is rubbed reciprocally, which results in a sharp decrease of the active sites. Therefore, the design of an ideal nanostructure for supported noble-metal catalysts that can overcome the above-mentioned limits and, thus, display high stability, is a great challenge in this field. [6] To address the problems of particle aggregation and detachment from the support, metal particles should be effectively separated from each other and firmly immobilized in the support. By consideration of this point, porousstructured materials might be a good candidate as supporting materials. Up to date, there are two main strategies for the preparation of mesoporous materials; [7, 8] one resorts to templating reagents. [7] Soft templates (such as triblock copolymers and surfactants) as well as hard templates (such as porous alumina and porous silica) play a key role in directing the formation of porous structures. The other strategy is based on metal-organic frameworks (MOFs) constructed from molecular building blocks. [8] The size and structure of their three-dimensional (3D) pores can be designed by using various molecular struts. In 2005, our group developed a general liquid-solid solution (LSS) strategy to synthesize a diverse range of nanocrystals, including noble-metal and oxide particles. [9,10] And recently, we developed a general emulsion-based bottom-up self-assembly (EBS) strategy to assemble monodisperse nanoparticles (NPs) into 3D colloidal spheres. [11,12] Herein, we describe a novel structure for preparing thermally stable nanocomposite catalysts: mesoporous multicomponent nanocomposite colloidal spheres (MMNCSs). We use both oxide (CeO 2 and TiO 2 ) and noble-metal (Ru, Rh, Pd, Pt, Au and Ag) nanoparticles as building block to fabricate the target colloidal spheres (Figure 1). The MMNCSs are expected to be a new type of ideal model catalysts that are stable at high reaction temperatures. As shown in Figure 1, the active sites of a noble metal in traditional supported catalysts decrease rapid...

The music of the spheres: Transition-metal phosphate colloidal spheres with one metal (Mn, Fe, Co, Ni, and Cu; see picture) or more than one metal (such as Fe-Ni, Co-Cu, Fe-Co-Cu, Fe-Co-Ni-Cu, Mn-Fe-Co-Ni-Cu, and Mn-Fe-Co-Ni-Cu-Zn) were synthesized in solution at low temperature. Porous and hollow iron phosphate spheres were prepared by adjusting the pH value of the reaction.

Synthesis of tubular nanomaterials has become a prolific area of investigation due to their wide range of applications. A facile solution-based method has been designed to fabricate uniform Bi 2 S 3 nanotubes with average size of 20 nm × 160 nm using only bismuth nitrate (Bi(NO 3 ) 3 ·5H 2 O) and sulfur powder (S) as the reactants and octadecylamine (ODA) as the solvent. Powder X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), and energy dispersive spectroscopy (EDX) experiments were employed to characterize the resulting Bi 2 S 3 nanotubes and the classic rolling mechanism was applied to explain their formation process.

Mesoporous materials have found a great number of important utilities due to their well-defined pore structure and high internal surface area, which are routinely synthesized with the assistance of block copolymers or templates. So far, a key challenge is how to assemble directly ligand-free inorganic nanocrystals into mesoporous structures, so that the high surface activity of ligand-free nanocrystals is not destroyed by further treatment to remove organic species or templates. In this paper, we report the direct assembly of highly uniform ZnO mesoporous ellipsoids from ligand-free ZnO nanocrystals of ∼5 nm. The size of the synthesized uniform ZnO mesoporous ellipsoids can be efficiently tuned from 132 × 75 to 190 × 111 nm (length × width), by varying the size and concentration of primary ZnO nanocrystal building blocks and the composition of the designed assembling solvent. The BET detection indicates that these ZnO mesoporous ellipsoids have high specific surface areas reaching to 136.57 m(2)/g, while their average BJH pore diameters are located at 8.8 nm. Especially, the high-resolution TEM images and XRD analysis revealed the occurrence of an oriented attachment mechanism in the assembly of uniform ZnO mesoporous ellipsoids, which supplied an important proof for the possibility of constructing stable three-dimensional structures by oriented attachment. The benefits of these ZnO mesoporous ellipsoids were demonstrated by their excellent photocatalytic activity under weak UV irradiation.