Silica nanotubes were synthesized from kaolin clay using surfactant intercalation, sulfuric acid and hydrothermal treatments.

The preparation of nanomaterials is a great challenge in the fields of synthetic chemistry and materials science because of the unusual properties that differentiate them from the bulk.1-13 To utilize and optimize the chemical/physical properties of nanoscale metals, a number of workers have focused on the control of the size and/or shape of nanoparticles as well as their selfassembly into ordered structures by developing effective synthetic techniques. Several techniques, such as gas condensation,14 irradiation,15,16 sol-gel,17,18 sonochemical deposition,19 and nanostructured templates20-22 for preventing the nanoparticles from irreversible aggregation, have been reported. Here, we report an effective well-confined redox method to prepare high-quality Agnanoparticles. Our strategy was based on a self-redox

Three inorganic-organic hybrid compounds with the formula CuL(VO2)(PO4), L) 4,4 -bipy, 1,10-phen, and 2,2 -bipy, were hydrothermally synthesized at 160℃ for 120h and characterized by single-crystal X-ray diffraction. The use of different bidentate organodiamine ligands in initial reaction systems gave rise to the variety in the structures of the products: Cu(4,4 -bipy)(VO2)(PO4) (1) and Cu(1,10-phen)(VO2)(PO4) (2) crystallize in a monoclinic system with space group C2/c, a) 21.952(4) Å, b) 8.0805(13) Å, c) 15.918(2) Å, â ) 110.689(4)°, and V) 2641.5(7) Å3, and a) 20.4557(12) Å, b) 11.6231(7) Å, c) 14.6422(8) Å, â) 127.5520(10)°, and V ) 2760.0(3) Å3, respectively. Cu(2,2 - bipy)(VO2)-(PO4) (3) crystallizes in a triclinic system with space group P1h, a ) 5.561(5) Å, b ) 10.271(9) Å, c ) 11.780(9) Å, R) 74.31(3)°, â) 79.98(3)°, ç) 85.74(3)°, and V) 637.6(9) Å3. The structures of 1 and 2 possess the same (VO2)(PO4) 2 four-membered rings, whereas the structure of 3 contains (VO2)(PO4) infinite chains. In terms of the organic parts, the Cu(4,4 -bipy) linear chains connect the (VO2)(PO4) 2 four-membered rings to build up a 3D framework in 1, whereas the Cu(1,10-phen)2+ and Cu(2,2 -bipy)2+ fragments link with the (VO2)(PO4) 2 four-membered rings and (VO2)(PO4) infinite chains to give two 1D structures of 2 and 3, respectively. Their thermal stabilities were investigated.

The hydrothermal reactions of V2O5, H2C2O4, Ni(NO3)2, ethylenediamine(en) or 1,2-diaminopropane(enMe) and water yield layered vanadium oxides with interlayer metal coordination complexes [Ni(en)2]0.5[V3O7] (1) and [Ni(enMe)2]0.5[H2enMe]0.5[V6O14] (2). 1 crystallizes in an orthorhombic system with space group Pbcn and cell parameters a) 16.617-(3)

A series of codoped nanocrystalline ceria compositions, Ce1-xMxBi0.4O2.6-x (M) Ca, Sr, and Ba; x) 0.01-0.15) were hydrothermally synthesized at 240℃ and characterized by powder X-ray diffraction, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. All as-made Ce1-xMxBi0.4O2.6-x crystallize in cubic fluorite-type structures and exhibit solid solution properties. The average particle sizes of Ce1-xMxBi0.4O2.6-x compositions obtained from hydrothermal systems were determined by the Scherrer equation and transmission electron microscopy to be approximately 32, 20, and 15nm for Ca, Sr, and Ba systems, respectively. The oxygen ionic conductivities of the codoped Ce1-xMxBi0.4O2.6-x were investigated by an ac (alternating current) impedance technique as a function of temperature and alkaline earth element contents. The highest ionic conductivity for Ce0.95Ca0.05Bi0.4O2.55 at 600℃ was 1.7_10-2 Sâcm-1 with the activation energy Ea) 46.3 KJâmol-1. In addition, the ionic transference numbers for the Ca, Sr, and Ba codoped systems were almost unit, showing their highly pure ionic conductivities.