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.

Synthesis and characterization of arginine-modified and europium-doped hydroxyapatite nanoparticle and its cell viability

The arginine-modified and europium-doped hydroxyapatite nanoparticles（HAP-Eu） were synthesized by hydrothermal synthesis.The prepared nanoparticles were characterized by transmission electron microscopy（TEM）,X-ray diffractometry（XRD）,Fourier transform infrared（FTIR） and zeta potential analyzer.The cell viability of HAP-Eu was tested by image flow cytometry.The results indicated that HAP-Eu is short column shapes and its size is approximately 100 nm,its zeta potential is about 30.10 mV at pH of 7.5,and shows no cytotoxicity in human epithelial cells and endothelial cells.

Synthesis,characterization and gas-sensing properties of Pd-doped SnO_2 nano particles

SnO2 nano particles with various Pd-doping concentrations were prepared using a template-free hydrothermal method.The effects of Pd doping on the crystal structure,morphology,microstructure,thermal stability and surface chemistry of these nano particles were characterized by transmission electron microscope,X-ray diffractometer and X-ray photoelectron spectroscope respectively.It was observed that Pd-doping had little effect on the grain sizes of the obtained SnO2 nano particles during the hydrothermal route.During thermal annealing,Pd-doping could restrain the growth of grain sizes below 500℃ while the grain growth was promoted when the temperature increased to above 700℃.XPS results revealed that Pd existed in three chemical states in the as-synthesized sample as Pd^0,Pd^2＋ and Pd^4＋,respectively.Pd^4＋ was the main state which was responsible for improving the gas-sensing property.The optimal Pd-doping concentration for better gas-sensing property and thermal stability was 2.0%-2.5% （mole fraction）.

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.

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.

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.

Effect of C/S Ratio on Morphology and Structure of Hydrothermally Synthesized Calcium Silicate Hydrate

The samples of the C-S-H series were synthesized by hydrothermal reaction of fumed silica, CaO and deionized water at initial C/S ratios between 1.0-1.7. Phase composition and structural and morphology characteristics of C-S-H samples were analyzed by XRD, IR and SEM. The experimental results showed that the d-spacing of （002）, （110） and （020） decreased, the d-spacing of （200） increased, and the d-spacing of （310） varied randomly, the polymerization of silica tetrahedra of C-S-H decreased, and morphology of C-S-H samples varied from sheet shapes to long reticular fibers as C/S ratio increased.

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 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.

Synthesis, Crystal Structure and Theoretical Calculations of a New Co(Ⅱ) Coordination Polymer Based on 5-Nitroisophthalic Acid and Bis(imidazol) Ligands

A new complex[Co（NIPH）（mbix）]n（1,H2NIPH = 5-nitroisophthalic acid,mbix =l,3-bis（imidazol-l-ylmethyl）benzene） has been hydrothermally synthesized and structurally characterized by elemental analysis,IR spectrum,UV spectrum,TG and single-crystal X-ray diffraction.Pink crystals crystallize in the triclinic system,space group P1 with a = 8.3797（8）,b= 10.2522（10）,c= 13.4244（13） A,α=94.820（2）,β=108.105（2）,γ=104.816（2）°,V=1042.84（17） A^3,C（22）H（17）CoN5O6,Mr = 506.34,Dc = 1.613 g/cm^3,F（000） = 518,Z = 2,μ（MoKα） =0.876 mm^（-1）,the final R = 0.0505 and wR = 0.1254 for 3267 observed reflections（I〉2σ（I））.The structure of 1 exhibits a two-dimensional network structure and is extended into a three-dimensional supramolecule through hydrogen bonds and n-n interactions.In addition,Natural Bond Orbital（NBO） analysis was performed by using the PBE0/LANL2 DZ method built in Gaussian 09 Program.The calculation results showed obvious covalent interactions between the coordinated atoms and Co（Ⅱ） ion.

Facile synthesis of UCNPs/Zn_xCd_(1-x)S nanocomposites excited by near-infrared light for photochemical reduction and removal of Cr(Ⅵ)

Photocatalysis driven by near-infrared（NIR）light is of scientific and technological interest for ex-ploiting solar energy.In this study,we demonstrate a facile hydrothermal process to synthesize core-shell nanoparticles combining upconversion nanoparticles（UCNPs）and alloyed ZnxCwhich can be excited using NIR or visible light.Morphologies,phase,and chemical composition have been investigated using field-emission scanning electron microscopy,transmission electron mi-croscopy,X-ray diffraction analysis,and atomic absorption spectroscopy.Moreover,we found that amorphous TiO2 layers existing in the final samples play an important role in formation ofyolk-shell nanoparticles,which bind the as-prepared ZnxCnanoparticlescan be tuna-ble by adjusting the amount of the Cd and Zn source compounds.The photochemical reduction of Cr（Ⅵ）in water has been performed to study the photocatalytic performance under irradiation by NIR light or a simulated solar light,showing efficient photoreduction and Cr（Ⅵ）removal over the/TiO2 yolk-shell nanoparticles.The as-prepared UCNPs@ZnxC/TiO2 nanoparticles show excellent production of hydroxyl radicals,which are responsible for the photochemical reduction of Cr（Ⅵ）to Cr（Ⅲ）.This study will provide an alternative strategy for en-vironmental wastewater treatment,making full use of solar energy.

Synthesis and Crystal Structure of a Two-dimensional Coordination Polymer Constructed by Thiophene-2,5-dicarboxylic Acid and 1,4-Bis(imidazol-1-yl)-butane

A metal-organic coordination polymer [Cd（tdc）（bimb）（μ2-H2O）]n （H2tdc = thiophe-ne-2,5-dicarboxylic acid, bimb = 1,4-bis（imidazol-l-yl）-butane） 1 has been hydrothermally synthe- sized and characterized by elemental analysis, IR, TG, luminescence spectrum and single-crystal X-ray diffraction. Colorless crystals crystallize in the triclinic system, space group P^-1 with a = 5.8945（3）, b = 10.3129（5）, c = 11.2226（5） A, a = 95.1430（10）,β = 97.9020（10）, γ = 90.5910（10）°, V = 672.84（6） A^3, C11H11CdN2O5S, Mr= 395.68, De = 1.953 g/cm^3, μ（MoKa） = 1.797 mm^-1, F（000） = 390, Z = 2, the final R = 0.0209 and wR = 0.0508 for 2514 observed reflections （I 〉 2σ（I））. The structure of 1 exhibits a two-dimensional layer-like structure.

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.

In Situ Synthesis of NaY Zeolite with Coal-Based Kaolin

NaY zeolites were in-situ synthesized from coal-based kaolin via thehydrothermal method. The effects of various factors on the structure of the samples were extensivelyinvestigated. The samples were characterized by N_2 adsorption, XRD, IR and DTG-DTA methods, andthe results show that the crystallization temperature and amount of added water play an importantrole in the formation of the zeolite structure. The 4A and P zeolites are the competitive phasepresent in the resulting product. However, NaY zeolites with a higher relative crystallinity,excluding impure crystals and the well hydrothermal stability, can be synthesized from coal-basedkaolin. These zeolites possess a larger surface area and a narrow pore size distribution, and thismeans that optimization of this process might result in a commercial route to synthesize NaYzeolites from coal-based kaolin.

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,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.

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 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.

One-step hydrothermal synthesis of S-defect-controlled ZnIn_(2)S_(4) microflowers with improved kinetics process of charge-carriers for photocatalytic H_(2) evolution

Engineering lattice defects in two-dimensional(2 D) sulfide semiconductors has been accepted as an effective strategy to enhance the efficiency of the solar-to-fuels conversion.Although many researches have proven the lattice defect-mediated photocatalytic activity of ZnIn_(2)S_(4),the artificial control of Sdefects for optimizing the charge-carrier kinetics process in ZnIn_(2)S_(4) has long been a challenging task.Herein,we report a facile one-step method to modulate the lattice S-content of ZnIn_(2)S_(4) microflowers(MFs) only through adjusting the used amount of S-precursor in the hydrothermal solution that contains the metal precursors with a fixed Zn/In stoichiometric ratio at 1:2.We also demonstrated that the Svacancies at the In facets were the main type of lattice defects in the formed ZnIn_(2)S_(4) MFs,which could enhance both the separation and migration processes of the photoinduced charge-carriers due to the existence of discrete defect energy-levels(DELs) and the reduced effective mass of electrons,as evidenced by the first-principles calculations and the electron spectra analyses.The ZnIn_(2)S_(4) MFs with the optimal content of S-vacancy obtained by a hydrothermal treatment of the precursors with the Zn/In/S stoichiometric ratio of 1:2:8 possessed the long-lived photoinduced electron(~94.64 ns) for contributing to the photo-physical and-chemical processes.Thus,upon visible light irradiation,the H_(2)-evolution rate of this sample reached ~2.40 mmol h^(-1) g^(-1) with an apparent quantum efficiency of ~0.16% at 420 nm even though only using 5 mg of photocatalysts without any cocatalysts.