Non-Isothermal Decomposion Kinetics of Supermolecule Compound [Eu(C_(10)H_9N_2O_4)(C_(10)H_8N_2O_4)(H_2O)_3]_2·phen·4H_2O

Europium(Ⅲ) compound with 2-oxopropionic acid salicyloyl hydrazone (C_(10)H_(10)N_2O_4,H_3L) and 1,10-phenan-throline (C_(12)H_8N_2,phen) has been prepared.A yellow prismatic crystal of the compound was obtained,and themolecule crystallized in the triclinic space group P-1.There are two 9-coordinated complex molecules in everystructure unit,where every Eu atom is coordinated by three water molecules and two tridentate C_(10)H_(10)N_2O_4 ligands,forming two stable pentacycles.The coordination polyhedron around Eu~(3+) was described as a single cap squareantiprism.In the crystal cell,there are one free 1,10-phenanthroline and four water molecules.The thermaldecomposition of the compound and its kinetics were studied by non-isothermal thermogravimetry.The Kissinger'smethod and Ozawa's method were used to calculate the activation energy value of the first-step decomposition.Thestages of the decompositions were identified by TG-DTG-DSC curve.The non-isothermal kinetic data were ana-lyzed by means of integral and differential methods.The possible reaction mechanism and the kinetic equationswere investigated by comparing the kinetic parameters.     

Isolation of hemoglobin with metal–organic frameworks Y(BTC)(H_2O)_6

The hierarchical metal-organic frameworks(MOFs),such as Y(BTC)(H_2O)_6,are prepared with yttrium nitrate and benzene-1,3,5-tricarboxylic acid at room temperature.The product is characterized by Fourier transform infrared(FT-IR),X-ray diffraction(XRD),scanning electron microscopy(SEM)and thermogravimetric analysis(TGA).The Y(BTC)(H_2O)_6 particles are sufficiently rigid for performing solid phase extraction and they exhibit favorable selectivity toward the adsorption of hemoglobin.The adsorption behavior of hemoglobin onto the Y(BTC)(H_2O)_6 fits the Langmuir adsorption model with a theoretical adsorption capacity of 555.6 mg g 1.An adsorption efficiency of 87.7%for 100μg mL 1hemoglobin in 1 mL sample solution(at pH 6.0)is achieved with 0.40 mg Y(BTC)(H20)6.77.3%of the retained hemoglobin is readily recovered using a 0.5%(m/v)SDS solution as the stripping reagent.Circular dichroism spectra indicated that the conformation of hemoglobin is maintained during the adsorption-desorption process.The MOFs material is applied for the isolation of hemoglobin from human blood and the purity of the obtained hemoglobin is further verified by sodium dodecyl sulfate polyacrylamide gel electrophoresis(SDS-PAGE).     

Molten salt synthesis and supercapacitor properties of oxygen-vacancy LaMnO_(3-δ)

Due to the unique structure of perovskite materials,their capacitance can be improved by introducing oxygen vacancy.In this paper,the LaMnO_(3-δ) material containing oxygen vacancy was synthesized by molten salt method in KNO_3-NaNO_3-NaNO_2 melt.The La-Mn-O crystal grows gradually in molten salt with the increase of temperature.It was confirmed that LaMnO_(3-δ) with perovskite structure and incomplete oxygen content were synthesized by molten salt method and presented a three-dimensional shape.LaMnO_(3-δ) stores energy by redox reaction and adsorption of OH-in electrolyte simultaneously.In comparison with the stoichiometric LaMnO_3 prepared by the sol-gel method,LaMnO_(3-δ) prepared by molten salt method proffered higher capacitance and better performance.The galvanostatic charge-discharge curve showed specific capacitance of 973.5 F/g under current density of 1 A/g in 6 M KOH.The capacitance of LaMn0_(3-δ) was 82.7%under condition of 5 A/g compared with the capacitance at the current of 1A/g,and the specific capacitances of 648.0 and 310.0 F/g were obtained after 2000 and 5000 cycles of galvanostatic charging-discharging,respectively.Molten salt synthesis method is relatively simple and suitable for industrial scale,presenting a promising prospect in the synthesis of perovskite oxide materials.     

Novel SrCe_(0.75)Zr_(0.20)Tm_(0.05)O_(3-δ) membrane for hydrogen separation

<正>Dense ceramic membranes with protonic and electronic conductivity have attracted considerable interest in recent years.In this paper,the powders of SrCe_(0.75)Zr_(0.20)Tm_(0.05)O_(3-δ) were synthesized via the liquid citrate method,and the membranes of SrCe_(0.75)Zr_(0.20)Tm_(0.05)O_(3-δ) were prepared by pressing followed by sintering.X-ray diffraction(XRD) was used to characterize the phase structure of both the powder and sintered membrane.The microstructure of the sintered membranes was studied by scanning electron microscopy(SEM).Hydrogen permeation through the SrCe_(0.75)Zr_(0.20)Tm_(0.05)O_(3-δ) membranes was carried out using gas permeation setup at 900℃.Hydrogen permeation flux of SrCe_(0.75)Zr_(0.20)Tm_(0.05)O_(3-δ) membrane reaches up to 0.042 mL/ min cm~2 at H_2 partial pressure of 0.4 atm.The hydrogen permeation fluxes obtained in this paper are similar to that of SrCe_(0.95)Tm_(0.05)O_(3-δ),and Zr doping can increase mechanical strength of SrCe_(0.75)Zr_(0.20)Tm_(0.05)O_(3-δ) membranes and the resistance to reducing circumstance.     

Role of Microstructure and Spectrum Features on the Catalysis Effect of Ce_(1-x)(Nd_(0.5)Eu_(0.5))_xO_(2-δ) Solid Solutions

Nanosized Ce_(1-x)(Nd_(0.5)Eu_(0.5))xO_(2-δ) solid solutions(x = 0.00~0.20) were synthesized by means of hydrothermal method.Then the solid solutions were ball milled with Mg_2Ni and Ni powders for 20 h to get the Mg_2Ni–Ni–5 mol% Ce_(1-x)(Nd_(0.5)Eu_(0.5))xO_(2-δ) composites.The structures and spectrum characteristics of the Ce_(1-x)(Nd_(0.5)Eu_(0.5))xO_(2-δ) solid solutions catalysts were analyzed systemically.XRD results showed that the doped samples exhibited single phase of CeO_2 fluorite structure.The cell parameters and cell volumes were increased with increasing the doped content.Raman spectrum revealed that the peak position of F_(2g) mode shift to higher wavenumbers and the peak corresponding to oxygen vacancies were observed distinctly for the doped samples.UV-Vis technique indicated that the absorption peaks of Eu~(3+) and Nd~(3+) ions appeared; the bandgap energy was decreased linearly.The electrochemical and kinetic properties of the Mg_2Ni–Ni–5 mol% Ce_(1-x)(Nd_(0.5)Eu_(0.5))xO_(2-δ) composites were measured.The maximum discharge capacity was increased from 722.3 mA h/g for x = 0.00 to 819.7 mA h/g for x = 0.16,and the cycle stability S_(20) increased from 25.0%(x = 0.00) to 42.2%(x = 0.20).The kinetic measurement proved that the catalytic activity of composite surfaces and the hydrogen diffusion rate were improved for the composites with doped catalysts,especially for the composites with x = 0.16 and x = 0.20.The catalysis mechanism was analyzed from the point of microstructure and spectrum features of the Ce_(1-x)(Nd_(0.5)Eu_(0.5))xO_(2-δ) solid solutions.     

CRYSTAL AND MOLECULAR STRUCTURE OF K(C_3H_(12)N_2)_2(HV_(10)O_(28_).8.5H_2O

<正> Preliminary information. Vanadium compounds plays an important role in catalysis since they have a property of easily changeable oxidation states. As a part of our study on vanadium compounds, the crystal structure of the title compound is reported, which is prepared by the reaction of (C_3H_(12)N_2)_2-V_2O_7, NaVO_3 with KOH in an aqueous solution.     

Low-temperature hydrogenation of maleic anhydride to succinic anhydride and γ-butyrolactone over pseudo-boehmite derived alumina supported metal(metal = Cu,Co and Ni) catalysts

The pseudo-boehmite derived alumina supported metal(Cu,Co and Ni) catalysts prepared by the impregnation method were investigated in hydrogenation of maleic anhydride(MA) to succinic anhydride(SA) and γ-butyrolactone.The catalysts were characterized by ICP-AES,N_2 adsorptiondesorption,XRD,H_2-TPR,CO-TPD,dissociative N_2O adsorption and TEM and the results showed that the alumina possessed mesoporous feature and the metal species were well dispersed on the support.Compared to Cu/Al_2O_3 and Co/Al_2O_3,Ni/Al_2O_3 exhibited higher catalytic activity in the MA hydrogenation with 92%selectivity to SA and nearly 100%conversion of MA at 140 °C under 0.5 MPa of H_2 with a weighted hourly space velocity of 2 h ~1(MA).The stability of Ni/Al_2O_3 catalyst was also investigated.     

Effects of ultrasonic impregnation combined with calcination in N_2 atmosphere on the property of Co_3O_4/CeO_2 composites for catalytic methane combustion

Co_3O_4/CeO_2 composites with high surface areas and ultrafine crystalline sizes for catalytic combustion of methane were firstly prepared by a new sol-gel method which combined ultrasonic impregnation treatment and calcination in N_2 atmosphere. The samples were characterized by various means such as nitrogen adsorption/desorption, X-ray diffraction(XRD), H_2 temperature-programmed reduction(H_2-TPR),X-ray photoelectron spectroscopy(XPS) and transmission electron microscopy(TEM). Results showed that the modified catalyst had the mesoporous structure, comparatively higher amount of surface oxygen and larger oxygen vacancies than others. As a result of the structure and surface composition merits, a high methane combustion conversion(50%) could be obtained at a low temperature of 262 °C for the modified Co_3O_4/CeO_2 composites catalysts. The experimental results demonstrated that ultrasonic impregnation treatment combined with the N_2 thermal treatment prior to calcination in air had a promising application for preparation of Co_3O_4/CeO_2 composites catalysts for low-temperature catalytic combustion of methane.     

AQUEOUS PHASE SYNTHESIS OF(RC_5H_4)_2Ti(O_2CC_6H_4X)_2

Nine complexes(RC_5H_4)_2Ti(O_2CC_6H_4X)_2(R=H,CH_3;X=H,o-Cl,o-OH,o-NH_2,o-NHPh)have been conveniently prepared by the reaction of(RC_5H_4)_2TiCl_2 with 2 equiv.sodium salts of corresponding carboxylic acidin aqueous solution containing acetylacetone.The carboxylate ligands inthe complexes coordinate to titanium atom in monodentate mode.     

Syntheses and Structures of Two New Cobalt Supramolecular Complexes, [Co(4,4'-bipy)_2(H_2O)_4]· [Co_2(4,4'-bipy)3O(H_2O)_8]·2TST·2(4,4'-bipy)·4H_2 and [Co(4,4'-bipy)_2(H_2O)_4]DSNT'4,4'-bipy

Two new cobalt(Ⅱ) supramolecular complexes [Co(4,4'-bipy)_2(H_2O) _4]·[Co_2(4,4'-bipy)3-(H_2O) _8]·2TST-2(4,4'-bipy)·4H_2O 1 and [Co(4,4'-bipy) _2(H_2O) _4]DSNT·4,4'-bipy 2 based upon the assembly of Co(Ⅱ), 4,4'-bipyridine (4,4'-bipy) and two new multifunctional organic ligands, 2,4,6-tris(4-sulfophenyl-amino)-1,3,5-triazine (H_3TST) and 2,4-bis(p-sulfanilato)-6-diethylamino-1,3,5-triazine (H_2DSNT), have been prepared by hydrothermal method and characterized by elemental analysis, IR spectrum, and single-crystal X-ray diffraction. The crystal structure of 1 is of monoclinic, space group P2_(1/n) with α= 13.599(4), b = 18.988(6), c = 22.995(7) A, β = 90.273(6)°, V= 5938(3) A~3, Z = 4, C_(56)H_(59)CO_(1.5)N_(13)O_(17)S_3, M_r = 1370.74, D_c = 1.533 g/cm~3,μ = 0.613 mm~(-1), F(000) = 2842, GOOF = 1.018, the final R = 0.0796 and wR = 0.1498 for 9019 observed reflections with I > 2o(I). The crystal structure of 2 belongs to the monoclinic system, space group C2/c with α = 18.864(6), b = 14.283(5), c = 20.246(7) A, β = 107.799(6)°, V = 5194(3) A~3, Z = 4, C_(49)H_(52)CoN_(12)O_(10)S_2, M_r = 1092.08, D_c = 1.397 g/cm~3, μ= 0.480 mm~(-1), F(000) = 2276, GOOF = 1.059, the final R = 0.0665 and wR = 0.1900 for 4887 observed reflections with I> 2σ(I). The results of X-ray crystal structure analysis revealed that complexes 1 and 2 exhibit layered supramolecular frameworks stabilized by electrostatic interactions, π-π interactions and hydrogen bonds.     

LOW-TEMPERATURE HEAT CAPACITIES AND THERMODYNAMIC PROPERTIES OF LANTHANUM AND CERIUM TRIISOTHIOCYANATE HYDRATESI (Ⅰ)——La(NCS)_3, 7H_2O AND Ce(NCS)_3. 7H_2O

The heat capacities of La(NCS)_3. 7H_2O and Ce(NCS)_3. 7H_2O have been measured from 13 to 300K with a fully-automated adiabatic calorimeter. The construction and procedures of the calorimetric system are described in detail. No obvious thermal anomaly was observed for both compounds in the experimental temperature range. The polynomial equations for calculating the heat capacity values of the two compounds in the range 13—300K were obtained by the least-squares fitting based on the experimental C_p data. The C_p values below 13K were estimated by using the Debye and Einstein heat Capacity functions. The standard molar thermodynamic functions were calculated from 0 to 300K. Gibbs energies of formation were also calculated.     

Synthesis of novel magnetic sulfur-doped Fe_3O_4 nanoparticles for efficient removal of Pb(Ⅱ)

In this work, we report the synthesis of magnetic sulfur-doped Fe_3O_4 nanoparticles (Fe_3O_4:S NPs) with a novel simple strategy,which includes low temperature multicomponent mixing and high temperature sintering. The prepared Fe_3O_4:S NPs exhibit a much better adsorption performance towards Pb(Ⅱ) than bare Fe_3O_4 nanoparticles. FTIR, XPS, and XRD analyses suggested that the removal mechanisms of Pb(Ⅱ) by Fe_3O_4:S NPs were associated with the process of precipitation (formation of PbS), hydrolysis,and surface adsorption. The kinetic studies showed that the adsorption data were described well by a pseudo second-order kinetic model, and the adsorption isotherms could be presented by Freundlich isotherm model. Moreover, the adsorption was not significantly affected by the coexisting ions, and the adsorbent could be easily separated from water by an external magnetic field after Pb(Ⅱ) adsorption. Thus, Fe_3O_4:S NPs are supposed to be a good adsorbents for Pb(Ⅱ) ions in environmental remediation.     

Synthesis,Structure and Characterization of a New Complex: [Mn(C_6H_(12)N_4)_2(H_2O)_4][Mn(H_2O)_6][SO_4]_2·6H_2O

A novel complex,[Mn(C_6H_(12)N_4)_2(H_2O)_4][Mn(H_2O)_6][SO_4]_2·6H_2O,was synthesized and hexagonal single crystals with centimeter-scale sizes were obtained by the method of solvent evaporation.It was characterized by elemental analysis,infrared spectrum,thermogravimetric analysis and X-ray single-crystal diffraction.The complex belongs to triclinic crystal system,space group P■ with a=9.3390(8),b=13.3520(13),c=16.3207(13)?,α=100.7160(3)°,β=90.1020(10)°,γ=109.9490(5)°,V=1874.9(3)?~3,Z=2,D_c=1.542 g/cm~3,M_r=870.64,μ=0.876 mm~(-1),T=293(2) K,F(000)=916 and S=0.990.The crystal structure determination displayed a distorted octahedral geometry around the manganese atom,which is bound to two nitrogen atoms from hexamethylenetetramine,acting as monodentate ligands,and to four aqua ligands.Variable-temperature magnetic measurements of the complex indicate the presence of weak antiferromagnetic interaction between manganese centers.     

ELECTRON PARAMAGNETIC RESONANCE STUDIES OF SINGLE CRYSTAL SODIUM HEXAMOLYBDOCHROMATE (Ⅲ)Cr~(3+)/Na_3(AlMo_6O_(24)H_6)·8H_2O

An X-band EPR study on a Na_3(CrMo_6O_(24)H_6)·8H_2O single crystal diluted by its isomor-phic compound Na_3(AlMo_6O_(24)H_6)·8H_2O at room temperature is reported. Using the least squares-fitting method to simulate the EPR data for principal planes, the Hamiltonian parameterswere obtained. The principal values of the g tensors are g_(ZZ) = 1.904, g_(XX)= 1.973, g_(YY)=1.933. The zero field splitting tensor parameters are D = 0.275 cm~(-1), E = 0.05 cm~(-1). The fielddependence of Cr~(3+) energy levels with field at different angles from the principal axes whenthe field is along the principal planes is calculated based on these experimental parameters.The isofrequency plots of calculated field vs. angle are also shown. They agree well with theexperimental results.     

An Ion-imprinted Silica Gel Polymer Prepared by Surface Imprinting Technique Combined with Aqueous Solution Polymerization for Selective Adsorption of Ni(Ⅱ) from Aqueous Solution

A novel Ni(Ⅱ) ion-imprinted silica gel polymer was prepared via the surface imprinting technique combined with aqueous solution polymerization by using 2-acrylamido-2-methyl-1-propanesulfonic acid(AMPS) as a functional monomer for the selective separation of Ni(Ⅱ) from aqueous solution. The sorbent showed good chemical and thermal stability. Kinetics studies indicated that the equilibrium adsorption was achieved within 10 min and the adsorption kinetics fitted well with the pseudo-second-order kinetic model. The maximum adsorption capacity of the ion-imprinted polymer towards Ni(Ⅱ) at the optimal p H of 7.0 was 66.22 mg·g~(-1). The relative selectivity coefficients of the sorbent were 9.23, 15.71, 14.72 and 20.15 for Ni(Ⅱ)/Co(Ⅱ), Ni(Ⅱ)/Cu(Ⅱ), Ni(Ⅱ)/Zn(Ⅱ) and Ni(Ⅱ)/Pb(Ⅱ), respectively. The adsorption isotherm fitted well with Langmuir isotherm model. The thermodynamic results indicated that the adsorption of Ni(Ⅱ) was a spontaneous and endothermic process. The sorbent showed good reusability evidenced by six cycles of adsorption/desorption experiments. The precision of this method is satisfactory. Thus, the prepared sorbent can be considered as a promising sorbent for selective separation of Ni(Ⅱ) in real water samples.     

Fabrication,adsorption and photocatalytic properties of ZnTi0.6Fe1.4O4/Carbon nanotubes composites

ZnTi_xFe_(2–x)O_4 and ZnTi_(0.6)Fe_(1.4)O_4/Carbon nanotubes(ZT_(0.6)F_(1.4)/CNTs) composites were prepared by chemical co-precipitation method. The composition, microstructure, magnetic property, adsorption and photocatalytic activity of the prepared samples were characterized by means of modern analytical techniques. The results indicated that ZT_(0.6)F_(1.4)/CNTs composites not only held the original special structure and excellent adsorption properties of CNTs, but also had suitable magnetic property and excellent photocatalytic activity. The removal rate of the samples on Rhodamine B(RhB) depended on the adsorption of CNTs and the photocatalytic degradation of ZT_(0.6)F_(1.4) in the composites. The maximum adsorption amount(q_m) of ZT_(0.6)F_(1.4)/CNTs with the mass ratios of ZT_(0.6)F_(1.4) to CNTs(mZ/C)=1 was up to 17.153 mg g~(–1) for RhB, its adsorption behavior was in accord with Langmuir model, and its photocatalytic degradation activity on RhB had a positive correlation with the content of ZT_(0.6)F_(1.4) in the sample. The experimental results indicate that the total removal rate of composite with mZ/C=1 on RhB was more than 95% and the composite had good decontamination capability on industrial dye wastewater. In addition, the samples can be recovered conveniently, activated easily and had good performance for recycling.     

HETERONUCLEAR COMPLEX CONTAINING COPPER-LANTHANIDE ARRAYS: THE SYNTHESIS AND CRYSTAL STRUCTURE OF Ln_2Cu_4L_8 (HL)_4(OH)_2(CIO_4)_4(H_2O)_(10)·2CH_3COCH_3 (Ln = Tb (1), Y (2); HL = 2-Pyridone C_5H_5NO)

Reaction of 2-pyridone, copper acetate and terbium(or yttrium) perchlorate in acetone with the moleratio 6: 2: 1 results in the formation of heteronuclear complex Ln_2Cu_4L_8 (HL)_4 (OH)_2 (ClO_4)_4 (H_20)_(10)2CH_3COCH_3(Ln = Tb (1), Y (2)). By recrystallizing (1) in CHCl_3 single crystals were obtained and thestructure was determined by four-circle diffractometer. Data showed that the crystal is in space groupC2/m with a=27. 454(9)A, b=13, 608A, c=30. 556(11)A, β=99. 89(3)°, v=11245. 7(7. 5)A~3. Thestructure was solved by a combination of Patterson method and Fourier technique. The final R value is0. 103. In the structure, four copper and two terbium ions are bridged by 2-pyridone anions to form anessentially octahedral Cu_4Tb_2 core. The terbium atoms are each eight-coordinate and the copper atomsare five-coordinate.     

Effect of synthesis solution pH of Co/γ-Al_2O_3 catalyst on its catalytic properties for methane conversion to syngas

The cobalt nanoparticles over γ-Al_2O_3 support were prepared via chemical reduction of CoCl_2·6H_2O using NaBH_4 with various values of pH in the range of 11. 92-13. 80. Synthesized catalysts were studied through X-ray diffraction( XRD),N_2 adsorption/desorption( BET),H_2-temperature programmed reduction( H_2-TPR),H_2-chemisorption,O_2 pulse titration and temperature programmed oxidation( TPO) methods. Obtained results exhibited the synthesis solution pH showed a significant influence on the activity and selectivity in partial oxidation of methane reaction. The methane conversion,CO selectivity and H_2 yield were enhanced by increasing of the synthesis solution pH. Compared to other catalysts,the catalyst that synthesized at pH of 13.80,showed a superior ability in syngas production with a H_2/CO ratio of near 2 and also a proper stability against deactivation during the partial oxidation of methane.     

Crystal structure and single crystal EPR of (NH_4)_2(15-crown-5)_3[Cu(mnt)_2] and (NH_4)_2(benzo-15-crown-5)_4[Cu(mnt)_2]·0.5H_2O

The X-ray crystal structures of (NH4)2(15-crown-5)3[Cu(mnt)2] (1) and (NH4)2(benzo-15-crown-5)4- [Cu(mnt)2]·0.5H2O (2) were determined. Two single crystals are composed of distinct structures of ammonium-crown ether supramolecular cation and [Cu(mnt)2]2? anion. The triple-decker dication in complex 1 and a sandwich dimmer in complex 2 were observed. X-Band EPR studies on the single crystals of both complex 1 and complex 2 have been carried out at room temperature, which revealed that complex 2 showed a perfect hyperfine structure of Cu whereas that of complex 1 could not be observed. The principal values and direction cosines of the principal axes of the g and A tensors were computed by a least-squares fitting procedure. The spin density of Cu(II) was estimated according to the principal values of the A tensors and compared well with the results calculated based on DFT method.     

MOLECULAR AND CRYSTAL STRUCTURES OF TETRANUCLEAR MOLYBDENUM CLUSTER[Mo_4(μ_3-O)_2O_4Cl_2(o-CH_3C_6H_4COO)~6]■

The new cluster[Mo_4(μ_3-O)_2O_4Cl_2(o-CH_3C_6H_4COO)_6]has been prepared by thereaction of molybdenum pentachloride and o-methylbenzoic acid.The crystal andmolecular structures were determined by the X-ray diffraction method.It crystallizesin the orthorhombic space group Pnna with cell parameters:Mr=1361.6,a=13.792(4),b=17.957(3),c=20.974(9) ,V=5194(2) ~3,Z=4,Dc=1.74/cm~3,F(OOO)=2704,μ(MoK )=11.0/cm,R=0.074.