One-step hydrothermal synthesis of 2,5-PDCA-containing MgAl-LDHs three-layer composite coating with high corrosion resistance on AZ31

The addition of 2,5-pyridinedicarboxylic acid(2,5-PDCA)to the Mg-Al LDH coating,which was prepared by one-step hydrothermal synthesis,had extremely enhanced the corrosion protection of AZ31 Mg alloy,although the 2,5-PDCA could not be intercalated into the interlayer spacing.The corrosion current density of 0.05 mol L^(−1)2,5-PDCA LDH containing LDH coating is 3.18 nA cm^(−2),reduced by two orders of magnitude compared to the LDH coating without inhibitor,and the corrosion inhibition efficiency of the coating is 98.05%.The coating formed on the surface of AZ31 was peeled off from the substrate by using a mechanical method and SEM observation of the cross-section showed that the coating consisted of three different layers.The innermost layer is a thick layer that consists of Mg(OH)_(2)and the intermediate layer is LDH,which is vertical to the substrate and the outmost layer is a thin but very dense deposit layer of LDH agglomerates with complexes of 2,5-PDCA and Mg.This kind of sediment/LDH/Mg(OH)_(2)three-layer composite structure was accountable for the increase in the corrosion resistance of AZ31 Mg alloy.

Hydrothermal synthesis, characterization and optical properties of La_2Sn_2O_7:Eu^(3+) micro-octahedra

Pyrochlore structure La2Sn2O7：Eu3＋ microcrystals with uniform octahedron shape were successfully synthesized via a hydrothermal route at 180 °C for 36 h. The crystal structure, particle size, morphologies, and optical properties of the as-synthesized products were investigated by XRD, TEM, SEM, EDS, FT-IR, Raman spectroscopy and PL. The effects of pH of precursor solution, precursor concentration, reaction temperature, and time were investigated. The results reveal that pH of the precursor solution not only plays an important role in determining the phase of the as-synthesized products, but also has a significant influence on the morphologies of the samples. High-quality and uniform octahedrons with an average size of about 700 nm could be easily obtained at the pH value of 12. The possible formation mechanism of octahedral-like La2Sn2O7：Eu3＋ microcrystals was briefly proposed. The photoluminescence spectra show that La2Sn2O7：Eu3＋ micro-octahedra display stronger emission in the range of 582-592 nm compared with the samples with other shapes.

Hydrothermal synthesis of nanosized ZSM-22 and their use in the catalytic conversion of methanol

ZSM‐22 zeolite with different crystal lengths was prepared using a modified hydrothermal method. Rotation speed, Si/Al molar ratio and co‐solvent have important effects on the crystal size of ZSM‐22. The nanosized zeolite samples were characterized by X‐ray diffraction, X‐ray fluorescence, nitrogen adsorption, scanning electron microscopy, temperature‐programmed desorption of am‐monia and solid state nuclear magnetic resonance. The catalytic performance of nanosized ZSM‐22 was tested using the conversion of methanol. Compared to conventional ZSM‐22, the nanosized ZSM‐22 zeolite exhibited superior selectivity to ethylene and aromatics and lower selectivity to propylene. Stability against deactivation was clearly shown by the nanosized ZSM‐22 zeolite. A higher external surface area and smaller particle size make this nanosized ZSM‐22 zeolite attractive for catalytic applications.

Effect of solvents on the morphology and structure of barium titanate synthesized by a one-step hydrothermal method

Tetragonal barium titanate was synthesized from barium hydroxide octahydrate and titanium tetrachloride through a simple one-step hydrothermal method.The effect of different solvents on the crystal structure and morphology of barium titanate nanoparticles during the hy-drothermal process was investigated.Except for ethylene glycol/water solvent,impurity-free barium titanate was synthesized in pure water,methanol/water,ethanol/water,and isopropyl alcohol/water mixed solvents.Compared with other alcohols,ethanol promotes the formation of a tetragonal structure.In addition,characterization studies confirm that particles synthesized in methanol/water,ethanol/water,and isopropyl al-cohol/water mixed solvents are smaller in size than those synthesized in pure water.In the case of alcohol-containing solvents,the particle size decreases in the order of isopropanol,ethanol,and methanol.Among all the media used in this study,ethanol/water is considered the optimum reaction media for barium titanate with high tetragonality(defined as the ratio of two lattice parameters c and a,c/a=1.0088)and small aver-age particle size(82 nm),which indicates its great application potential in multilayer ceramic capacitors.

Synthesis and Electrochemical Property of Flowerlike LiFePO4 by Poly（ethylene glycol）-assisted Hydrothermal Process

Flowerlike LiFePO4 particles self-assembled by plate-like crystals with about 200 nm thickness were prepared by the poly（ethylene glycol）-assisted hydrothermal synthesis. Poly（ethylene glycol） in the hydrothermal system played an important role in reducing the thickness of the plate-like LiFePO4 crystals as a co-solvent and forming the flower- like structure as a soft template. The flowerlike LiFePO4 exhibits high discharge capacity of 140 mAh/g and shows quite good cycling performance in the lithium-ion batteries. Con- sidering that the conductive carbon in the obtained LiFePO4 is negligible, the excellent cell performance suggests that the flowerlike LiFePO4 is a promising cathode material for the lithium-ion batteries.

Hydrothermal synthesis of monodisperse Zn_(x)Cd_(1-x)S spheres and their photocatalytic properties

Monodisperse ZnxCd1-xS spheres were successfully fabricated with a high yield by a facile hydrothermal route.The as-prepared samples were characterized by X-ray diffractometry,scanning electron microscopy and UV-vis diffusion reflectance spectroscopy.The results indicate that all the prepared samples have the same hexagonal wurtzite phase and exhibit good size uniformity and regularity.Degradation of rhodamine-B（RhB） was used to evaluate the photocatalytic activities of ZnxCd1-xS samples.Zn0.4Cd0.6S possessed the best photocatalytic activity and exhibited high stability during the reaction.

Hydrothermal Synthesis and Crystal Structure of a Zinc Complex:[Zn_(2.5)(phen)(BDC)_2(OH)] (phen = 1,10-Phenanthroline, BDC = Benzene-1,4-dicarboxylic Acid)

A metal-organic coordination polymer [ZnE.s（phen）（BDC）2（OH）]2 （phen = 1,10- phenanthroline, BDC = benzene-1,4-dicarboxylic acid） 1 has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction, elemental analyses and IR spectroscopy. The complex crystallizes in the triclinic system, space group PI with a = 11.199（2）, b = 11.593（2）, c = 11.865（3）/A, α= 99.330（1）, β = 111.506（1）, γ = 104.804（1）^o, V= 1328.4（5）A^3, Dc= 1.722 g/cm^3, Z = 1, Mr = 1377.82, F（000） = 692,μ（MoKa） = 2.306 mm^-1, S = 1.093, R= 0.0281 and wR = 0.0756 for 4179 observed reflections （I 〉 2σ（/））. The coordination polyhedron around Zn（II） can be described as a tetrahedron, trigonal bipyramid and octahedron. It is worth noting that the crystal structure of 1 is composed of tetranuclear zinc clusters linked by {ZnO6} units.

Hydrothermal Synthesis,Crystal Structure and Electrochemical Properties of Complex Cu(α-Furacrylic acid)_2(phen)

The title complex （C26H18CuN206, Mr= 517.96） has been synthesized by the reaction of α-furanacrylic acid with 1,10-phenanthroline （phen） in the solvent mixture of water and methanol. Crystal data： monoclinic, space group C2/c with a = 2.2927（4）, b = 1.01248（18）, c = 1.05061（18） nm, β = 111.188（3）°, V= 2.274（7） nm^3, Dc = 1.513 g/cm^3, Z = 4, F（000） = 1060,μ = 1.007mm^-1, R = 0.0320 and ωR = 0.0781. The crystal structural analysis shows that the copper atom is coordinated with four oxygen atoms from two α-furacrylic acids and two nitrogen atoms from 1,10-phenanthroline, giving a distorted octahedral coordination geometry. The result of electrochemical analysis shows that the electron transfer in the electrode reaction is quasi-reversible.

Synthesis of LiFePO_4 /C as cathode material by a novel optimized hydrothermal method

Olivine LiFePO 4 , as a cathode material for lithium ion batteries, was prepared by a novel optimized hydrothermal method; afterwards, the product mixed with glucose was two-step （350℃ and 700℃） calcinated under high-purity N 2 atmosphere to obtain the LiFePO 4 /C composite. The study on the hydrothermal preparation method, which focused on the influences of molar ratios, initial pH value, reaction temperature, and duration, was made to promote the resultant performances and to investigate the relations between the performances and the reaction conditions. The resultant samples were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and electrochemical tests, which include charge-discharge, electrochemical impedance spectroscopy, and cyclic voltammetry. The result shows that the optimal hydrothermal condition is to set the Li：Fe：P molar ratio at 3：1：1 and the reaction temperature at 180℃ for 5 h duration with an initial pH value of 7. The optimized sample, with an average particle size of 100 to 300 nm and a discharge capacity of 118.2 mAh·g-1 at 0.1C, exhibits a stable and narrow-gapped charge-discharge platform and small capacity losses after cycles.

Hydrothermal Synthesis, Crystal Structure and Photoluminescent Property of a Zinc(II) Coordination Polymer Assembled by Phthalate and 4,4′-Bipyridine

A metal-organic coordination polymer {[Zn（Pht）（4,4＇-bipy）（H2O）2]·2H2O}n （Pht = phthalate, 4,4＇-bipy = 4,4＇-bipyridine） 1 has been hydrothermally synthesized and characterized by elemental analysis, IR, TG, fluorescence spectrum and single-crystal X-ray diffraction. Yellow crystals crystallize in the monoclinic system, space group P2/n, a = 7.6346（14）, b = 11.316（2）, c = 10.8133（19） ,A, β = 92.A.A,A.（3）°, V = 933.3（3） A^3, C18H20N2O8Zn, Mr = 457.73, Dc = 1.629 g/cm^3, F（000） = 472, Z = 2,μ（MoKa） = 1.367 mm^-1, the final R = 0.0323 and wR = 0.0821 for 1859 observed reflections （Ⅰ〉 2σ（Ⅰ））. The structure of 1 exhibits a two-dimensional bilayer framework formed by hydrogen bonding interactions. Furthermore, 1 shows yellow photoluminescent property at room temperature.

High quality Sb-doped SnO2 electrodes with high oxygen evolution potential prepared by in situ hydrothermal synthesis method

High quality Sb-doped SnO2 electrode, with high oxygen evolution potential of 3.0 V, was successfully synthesized on the Ti substrates by in situ hydrothermal synthesis method.

Hydrothermal Synthesis, Crystal Structure and Photoluminescent Property of a New Isophthalate- bridged Zinc(II) Polymer with One-dimensional Chain Structure: [Zn(ipt)(im)_2]_(2n)·3nH_2O (ipt = Isophthalate, im = Imidazole)

A new metal-organic coordination polymer [Zn（ipt）（im）2]2n·3nH2O 1 has been obtained by using hydrothermal synthesis and characterized by elemental analysis, IR, TG, fluorescence spectrum and single-crystal X-ray diffraction. The complex crystallizes in monoclinic, space group P2（1/n） with a = 10.653（3）, b = 17.891（6）, c = 10.743（4）A^°,β= 117.093（5）°, V= 1822.9（10） A^°3, Mr= 413.65, Dc = 1.507 g/cm^3,/t（MoKa） = 1.390 mm^-1, F（000） = 840, Z = 4, the final R = 0.0444 and wR = 0.1066 for 2434 observed reflections （I〉 2σ（I））. Furthermore, compound 1 shows blue photoluminescent property at room temperature.

Hydrothermal Synthesis and Characterization of a Novel Supramolecular Network Compound [Co(IN)_2(H_2O)_4](IN=Isonicotinate)

A novel supramolecular compound, [Co(IN)_2(H_2O)_4](1), was synthesized by means of the hydrothermal method and its structure was characterized with elemental analysis, FT-IR spectrum, TGA and X-ray diffraction. Though the unit cell structure of the title compound is only monomeric, all these units as building blocks are assembled into a novel three-dimensional supramolecular network via the widely hydrogen-bonding and π-π stacking interactions.

Hydrothermal synthesis of Y(OH)_3,Y(OH)_3:Eu^(3+) nanotubes and the photoluminescence of Y(OH)_3:Eu^(3+),Y_2O_3:Eu^(3+)

The phase and morphology transformation during the hydrothermal treating process of Y2O3 was evaluated with X-ray difference (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), particle size and specific surface area determination. The results showed that the cubic Y2O3 did not transfer into hexagonal Y(OH)3 in pure water. Therefore, pure hexagonal Y(OH)3 with nanotube and microrod morphologies were obtained by hydrothermal treating Y2O3 at 150 oC for 12 h in 15 ml of 2 mol/L NaOH solution with and without PVA or PEG. It was suggested that the characteristic preferential growth of Y(OH)3 was attributed to the structure anisotropy of hexahedron Y(OH)3. The addition of PVA or PEG could promote the forming process of nanotubes by selective adsorption on different crystal planes, which altered the growth rate along different directions and resulted in the diffusion limit of constructing ions in the center top of rods. Finally, Y(OH)3:Eu and Y2O3:Eu nanotubes were also synthesized by using this method, and their photoluminescence properties were evaluated.

Hydrothermal Synthesis,Structure and Properties of a 3D Pillar-layered Metal-organic Framework Based on Amino-arenedisulfonate Ligand

One novel metal-organic framework(MOF), [Ba(L)(HO)](1, HL =aniline-2,5-disulfonic acid), has been synthesized by hydrothermal method. Each barium atom is eleven-coordinated into a distorted monocapped pentagonal antiprismatic arrangement. Compound 1 shows an interesting 3 D pillar-layered structure constructed from 2 D inorganic layers[Ba(SO)(HO)]and organic pillars of phenyl moieties of L2-linkages. The inorganic layers are supported by the organic pillars, generating a novel 3 D open framework structure with {3, 4~6, 5~5, 6~5,7~4}2{3}{5} topology. The result of fluorescence measurement can reveal that the decayed emission band centered at 492 nm may be caused by the interactions of the ligands and the metal ions.Compound 1 exhibits selective toward the adsorption of COover Nat 273 K.

Microwave Hydrothermal Synthesis PZT of Nanometer Crystal

It was focused on the applications and developments of microwave hydrothermal synthesis piezoelectric ceramic powder. The microwave hydrothermal vessel was designed and manufactured. The microwave hydrothermal synthesis system was established and the PZT piezoelectric ceramic powder was synthesized. XRD and TEM have been used to characterize the products in detail. The diameter of the PZT powder particle is from 40 to 60 nm.

Hydrothermal Synthesis, Crystal Structure and Electrochemical Properties of the Complex Cu(o-Methylbenzoic acid)_2(2,2′-bipy)·(H_2O)

The title complex （C26H24CuN2O5, Mr = 508.01） has been synthesized by o-methylbenzoic acid, 2,2＇-bipyridine （bipy） and copper perchlorate in the mixed solvent of water and methanol. It crystallizes in orthorhombic, space group P212121 with a = 0.70814（10）, b = 1.6953（3）, c = 1.9539（3） nm, V= 2.3457（6） nm^3, De= 1.439 g/cm^3, Z = 4,μ = 0.971 mm^-1, F（000） = 1052, R = 0.0432 and wR = 0.0860. The structural determination shows that the copper atom is coordinated by three oxygen atoms from two o-methylbenzoic acids and one water molecule together with two nitrogen atoms from 2,2＇-bipyridine, giving a distorted square-pyramidal coordination geometry. The cyclic voltammetric behavior of the complex is also discussed.

Hydrothermal Synthesis,Crystal Structure and Thermal Stability of a Binuclear Copper(Ⅱ) Complex with 3-(Pyridin-2-yl)-1,2,4-triazole

One novel binuclear copper（Ⅱ） complex [Cu 2 （Hpt） 2 （CO 3） 2 （H 2 O） 2 ]·H 2 O with copper carbonate and 3-（pyridin-2-yl）-1,2,4-triazole （Hpt） was hydrothermally synthesized and characterized by IR and X-ray diffraction analysis.The complex crystallizes in triclinic,space group P2 1 /n with a=0.6862（1）,b=0.7805（1）,c=1.1983（2） nm,α=72.03（2）,β=107.72（3）,γ=75.28（2）o,V=0.5884 nm 3,D c=2.105 g/cm 3,Z=1,F（000）=357,GOOF=1.041,the final R=0.01859 and wR=0.04348.The whole molecule is composed of two cooper ions,two Hpt molecules,two carbonate and three water molecules,forming a binuclear structure.The crystal structure shows that the cooper ion is coordinated with three nitrogen atoms from two Hpt molecules,two oxygen atoms from one carbonic acid and one water molecule,forming a distorted square pyramidal geometry.The TG analysis result shows that the title complex is stable under 131.0 ℃.

Hydrothermal Synthesis and Crystal Structure of a New Nickel(Ⅱ) Complex with 3,4-Pyridinedicarboxylic Acid and 1,4-Bis(imidazol-1-ylmethyl)-benzene Ligands

A metal-organic coordination polymer [Ni（PDB）（bix）（H20）]n （H2PDB = 3,4-pyri- dinedicarboxylic acid, bix = 1,4-bis（imidazol-l-ylmethyl）-benzene） 1 has been hydrothermally synthesized and characterized by elemental analysis, IR, TG and single-crystal X-ray diffraction. Blue crystals crystallize in the triclinic system, space group PI with a = 9.1849（8）, b = 9.2065（9）, c = 12.9308（12） °, a = 103.3070（10）, β = 104.7160（10）, y = 90.5900（10）°, V = 1026.42（16）/k3, C21H19NsNiOs, Mr = 480.12, Dc = 1.553 g/cm3, F（000） = 496, Z = 2,/l（MoKa） = 0.991 mm-1, the final R = 0.0325 and wR = 0.0799 for 3561 observed reflections （I 〉 2σ（I））. The structure of 1 exhibits a two-dimensional network structure.

Hydrothermal Synthesis and Crystal Structure of a New Three-dimensional Heterometallic Coordination Polymer

A new 3d-4fheterometallic polymer {[Sm2Cu（PDC）2（SO4）2（H20）6]·2H2O}n 1 has been synthesized by Sm2O3, Cu（SO4）2·5H2O and pyridine-3,5-dicarboxylic acid under hydrothermal conditions. The compound crystallizes in triclinic system, space group Pi, with a = 6.352（7）, b = 10.040（10）, c = 10.315（11） A, α = 94.958（14）, β = 95.556（7）, γ = 99.747（14）°, V = 641.7（12）A3, Z = 1, M, = 1030.63, Dc= 2.651 Mg/m3,μ = 5.615 mm-1, F（000） = 491, the final R = 0.0491 and wR = 0.1345 for 2098 observed reflections with I 〉 2σ（I）. The compound is a three-dimensional network structure in which infinite lanthanide-carboxylate chains are linked by [Cu（$04）2]2- metalloligands to form a mixed-metal coordination network.