锡镀层钨-硫彩色簇合物膜的红外光谱和光电子能谱表征

目前,关于金属镀层表面钨-硫彩色簇合物功能修饰膜的研究较少。在Stb32钢板表面电镀锡,利用(NH4)2WS4溶液与锡镀层表面发生配位化学反应,得到钨-硫彩色簇合物膜,膜层具有金属光泽,加热处理后其颜色发生变化。用红外光谱(FT-IR)、远红外光谱(F-IR)、拉曼光谱(FT-Raman)和光电子能谱(XPS)和俄歇电子能谱(AES)研究了簇合物膜层的组成、结构和反应机理。结果表明,簇合物膜中存在W-S-Sn配位键、端基W-S和端基W-O键;膜层由W,S,Sn和O元素组成,在膜层表面W,S,Sn,O分别呈W6+,S6+,S4+,S2-,Sn2+,O2-形式;在膜内层W6+,W4+共存,其他元素分别呈Sn2+,S2-,O2-形式;膜为多分子层结构,膜层厚150~260 nm,其中红棕色膜层的组成(原子分数)为29.5%Sn,21.2%W,32.5%S,16.8%O。

赣南狮吼山硫铁-钨多金属矿床H-O-S同位素组成特征

狮吼山硫铁-钨多金属矿床位于银坑-青塘整装勘查区北部,是赣南地区唯一大型硫铁矿床。磁黄铁矿-黄铁矿(-黄铜矿-白钨矿)矿体赋存于石炭系梓山组上段地层中含铁、含钙层位,主要形成于石英-硫化物阶段。本文通过分析原生矿石矿物中H-O-S同位素组成特征,结合Pb同位素和成矿年代测试结果,探讨成矿流体来源及成矿演化过程。矿石硫化物中δ^(34)S组成特征(-5. 50‰～-0. 20‰,集中于-3. 0‰～0. 0‰)显示,硫源以岩浆硫为主,较宽的变化范围预示成矿流体遭受了叠加和改造作用。δD-δ^(18)O同位素组成主要集中于岩浆水与变质水重叠区域(δD=-74. 4‰～-48. 0‰,δ^(18)O_(H_2O)=3. 76‰～10. 86‰),说明成矿流体以岩浆水和变质水为主,后期有少量的天水混入。综合分析认为,该矿床成矿流体主要来自深部岩浆水,岩浆热液与含钙地层的接触交代作用形成大规模变质流体,再加上少量的天水混入,流体间的不混溶作用使成矿物质在岩体与含钙层位接触部位富集沉淀,形成热液充填交代型矿床。

Effect of WS_2 addition on electrical sliding wear behaviors of Cu-graphite-WS_2 composites

Four kinds of Cu-based composites with different mass ratios of graphite and WS2 as lubricants were fabricated by hot-pressing method. Electrical sliding wear behaviors of the composites were investigated using a block-on-ring tribometer rubbing against Cu-5%Ag alloy ring. The results demonstrated that 800 ~C was the optimum sintering temperature for Cu-graphite-WS2 dual-lubricant composites to obtain the best comprehensive properties of mechanical strength and lubrication performance. Contact voltage drops of the Cu-based composites increased with increasing the mass ratio of WS2 to graphite. The Cu-based composite with 20% graphite and 10% WS2 showed the best wear resistance due to the excellent synergetic lubricating effect of graphite and WS2. The reasonable addition of WS2 into the Cu-graphite composite can remarkably improve the wear resistance without much rise of electrical energy loss which provides a novel principle of designing suitable sliding electrical contact materials for industrial applications.

Fabrication and characterization of tungsten-containing mesoporous silica for heterogeneous oxidative desulfurization

A series of functional,tungsten-containing mesoporous silica materials（W-SiO2） have been fabricated directly from an ionic liquid that contained imidazole and polyoxometalate,which acted as mesoporous template and metal source respectively.These materials were then characterized through X-ray diffraction（XRD）,transmission electron microscopy（TEM）,Raman spectroscopy,Fourier transform infrared spectra（FTIR）,diffuse reflectance spectra（DRS）,and N2 adsorption-desorption,which were found to contain tungsten species that were effectively dispersed throughout the structure.The as-prepared materials W-SiO2 were also found to possess a mesoporous structure.The pore diameters of the respective sample W-SiO2-20 determined from the TEM images ranged from 2 to 4 nm,which was close to the average pore size determined from the nitrogen desorption isotherm（2.9 nm）.The materials were evaluated as catalysts for the heterogeneous oxidative desulfurization of dibenzothiophene（DBT）,which is able to achieve deep desulfurization within 40 min under the optimal conditions（Catalyst（W-SiO2-20）= 0.01 g,temperature = 60℃,oxidant（H2O2）= 20 μL）.For the removal of different organic sulfur compounds within oil,the ability of the catalyst（W-SiO2-20） under the same conditions to remove sulfur compounds decreased in the order：4,6-dimethyldibenzothiophene Dibenzothiophene Benzothiophene 1-dodecanethiol.Additionally,they did not require organic solvents as an extractant in the heterogeneous oxidative desulfurization process.After seven separate catalytic cycles,the desulfurization efficiency was still as high as 90.3%.From the gas chromatography-mass spectrometer analysis,DBT was entirely oxidized to its corresponding sulfone DBTO2 after reaction.A mechanism for the heterogeneous desulfurization reaction was proposed.

Tungsten carbide-reduced graphene oxide intercalation compound as co-catalyst for methanol oxidation

Highly dispersed tungsten carbide（WC） nanoparticles（NPs） sandwiched between few-layer reduced graphene oxide（RGO） have been successfully synthesized by using thiourea as an anchoring and inducing reagent.The metatungstate ion,[H2W（12）O（40）]^6-,is assembled on thiourea-modified graphene oxide（GO） by an impregnation method.The WC NPs,with a mean diameter of 1.5 nm,are obtained through a process whereby ammonium metatungstate first turns to WS2,which then forms an intercalation compound with RGO before growing,in situ,to WC NPs.The Pt/WC-RGO electrocatalysts are fabricated by a microwave-assisted method.The intimate contacts between Pt,WC,and RGO are confirmed by X-ray diffraction,scanning electron microscope,transmission electron microscope,and Raman spectroscopy.For methanol oxidation,the Pt/WC-RGO electrocatalyst exhibited an electrochemical surface area value of 246.1 m^2/g Pt and a peak current density of1364.7 mA/mg Pt,which are,respectively,3.66 and 4.77 times greater than those of commercial Pt/C electrocatalyst（67.2 m^2/g Pt,286.0 mA/mg Pt）.The excellent CO-poisoning resistance and long-term stability of the electrocatalyst are also evidenced by CO stripping,chronoamperometry,and accelerated durability testing.Because Pt/WC-RGO has higher catalytic activity compared with that of commercial Pt/C,as a result of its intercalated structure and synergistic effect,less Pt will be required for the same performance,which in turn will reduce the cost of the fuel cell.The present method is facile,efficient,and scalable for mass production of the nanomaterials.

Ultrahigh photocatalytic hydrogen evolution performance of coupled 1D CdS/1T-phase dominated 2D WS_(2) nanoheterojunctions

Solar-powered photocatalytic hydrogen production from water using semiconductors provides an eco-friendly and promising approach for converting solar energy into hydrogen fuel.Bulk semiconductors generally suffer from certain limitations,such as poor visible-light utilization,rapid recombination of charge carriers,and low catalytic capability.The key challenge is to develop visible-light-driven heterojunction photocatalysts that are stable and highly active during the water splitting process.Here,we demonstrate the integration of one-dimensional(1D)Cd S nanorods with two-dimensional(2D)1 T-phase dominated WS_(2) nanosheets for constructing mixed-dimensional heterojunctions for the photocatalytic hydrogen evolution reaction(HER).The resulting 1D CdS/2D WS_(2) nanoheterojunction exhibited an ultrahigh hydrogen-evolution activity of~70 mmol·g^(-1)·h^(-1) that was visible to the naked eye,as well as long-term stability under visible light illumination.The results reveal that the synergy of hybrid nanoarchitectures and intimate interfacial contact between the 1D Cd S nanorods and 1T-phase dominated 2D WS_(2) nanosheets facilitates charge carrier transport,which is beneficial for achieving superior hydrogen evolution.

Synthesis and Characterization of syn-[(η~5-C_5Me_5)_2W_2(S)_2(μ-S)_2].0.5anti-[(η~5-C_5Me_5)_2W_2(S)_2(μ-S)_2]

The reactions of [PPh4][(5-C5Me5)WS3] with equimolar Hg2Cl2 in DMF produced syn-[(5-C5Me5)2W2(S)2(-S)2]?.5anti-[(5-C5Me5)2W2(S)2(-S)2] 1. The structure of 1 was determined by single-crystal X-ray diffraction analysis. 1 crystallizes in the triclinic space group P (No. 2) with a = 8.400(2), b = 8.729(2), c = 23.329(8) ? ?= 93.329(8), ?= 93.446(2), ?= 96.673(1)? V = 1725.1(5) ?, Z = 2, C30H45S6W3, Mr = 1149.60, Dc = 2.213 g/cm3, F(000) = 1086, (MoK? = 10.37 cm-1 and T = 193 K. With the use of 6199 observed reflections (I > 3.0(I)), the structure was refined to R = 0.053 and wR = 0.065. 1 consists of one syn-[(5-C5Me5)2W2(S)2(-S)2] and one-half of anti-[(5-C5Me5)2W2(S)2(-S)2]. Both syn- and anti-isomer contain a four-membered W2(-S)2 ring. The WW distances of the syn and anti forms are 2.8973(5) and 2.9113(8) ? respectively.

Structural Characterization of Chiral Sulfido Cluster(η~5-C_5H_5) WFeCo(CO)_8 (μ_3-S)

The chiral sulfido cluster (η5-C5H5)WFeCo(CO)8(μ3--S) was synthesized by refluxing a solution of HFe2Co(CO)9 (μ3,--S) and (η5-C5H5)Fe(CO)3Cl in tetrahydrofuran. It was characterized by elemental analysis, IR and 1H/13C--NMR. Theproposal concerning mechanism was discussed herewith and the structure was reportedas well. Crystallographic data: Mr= 563. 85, monoclinicl P21/n(# 14); a= 8. 009(2), b= 17. 600(5), c=12. 003(4) A; β=95. 91(2)°; V= 1683. 0 (9) A3; Z=4;Dc=2. 22 g. cm-3; F(000) = 1048, μ=89. 27 cm-1 ; final R=0. 039 and Rw=0. 049for 2121 observable reflections with (I≥3. cσ(I) ). The crystal structure determinationshows that S atom coordinates to all three metal (W,Fe,Co) atoms in a μ3,-fashion,thetitle cluster core has the tetrahedral skeleton.

Complexation extraction of scheelite and transformation behaviour of tungsten-containing phase using H_(2)SO_(4) solution with H_(2)C_(2)O_(4) as complexing agent

The extraction of tungsten from scheelite was carried out using a sulfuric acid solution with oxalic acid as the chelating agent.Tungsten was obtained in the form of highly soluble hydrogen aqua oxalato tungstate H_(2)[WO_(3)(C_(2)O_(4))·H_(2)O] during the leaching process,while calcium remained in the residue as calcium sulfate dihydrate(CaSO4·2H2O).About 99.2%of the tungsten was leached at 70℃,1.5 mol/L sulfuric acid,1 mol/L oxalic acid,a liquid/solid ratio of 25:1(mL/g),an oxalic acid to sulfuric acid molar ratio of 1:1,a stirring speed of 300 r/min and a leaching time of 2 h.H_(2)[WO_(3)(C_(2)O_(4))·H_(2)O]was thermally decomposed into tungstic acid(H_(2)WO_(4)),and tungsten trioxide(WO_(3))was directly produced by calcining H_(2)WO_(4) at 700℃ for 2 h.The surface chemical reaction was determined to be the controlling step during tungsten leaching,and the apparent activation energy was calculated to be 51.43 kJ/mol.

Charge-transfer Salt of Tungstogermanate Heteropolyanion and Dibenzotetrathiofulvalene

Charge-transfer salt (dbtf),HGeW12O40. 4H2O(C84H57O44S24GeW12)was synthesized by electrocrystallization and characterized by IR and electronic spectra.Its magnetic and conducting properties and crystal structure were determined. The titlesalt crystallized in triclinic system with P1 space group. Its cell parameters are reflexions

MULTIPLE CENTER d-β ORBITALS AND CHARGE TRANSFER OF HETERONUCLEAR COUSTERS WITH CUBANE TYPE (Mo_3S_4)_xM^n+ (x=1, 2, M = Cu, W, Ni, Sb. Mo, Sn, Cu_2; n = 4,8)

In this work, with the analysis on MO and electronic structure for a series of heteronuclear cluster with cubane type (Mo4S1 )xMn1(x=1.2. M = Cu, W, Ni, Sb, Mo, Sn, Cu2) we found that it is with the multiple center d-pir orbitals that the ligand Mo3S44+ bonds to the M atom to form these class clusters. It is revealed that the charges transfer from the M atom to Mo atom of the ligand Mo3S44+ and its relationship with the MC (multiple center) d-pπ orbitals. Based on the charge transfer the electronic spectrum and the magnetic property of some cubane clusters have been discussed.

Syntheses, Structures and Reactivity of Incomplete Cubane-like Compound[{ W_3S_4} {S_2P(OEt)_2}_4(H_2O)]and Its Derivates

The first successful attempt to prepare W_3S_4 {S_2P (OEt )_2}_4(H_2O) in organic phase is reported. Its substitution and addition reactions are investigated systematically, and the substitution sequences of the 'loose' ligands are determined. The crystallographic data of the cluster compounds with [W_3S_4]￣(4+) and [W_3CuS_4]￣(5+) cores are compared and their UV-Vis spectra are firstly reported. Thus, the 'quasi-aromaticity' of the [W_3S_4]￣(4+) core of these cluster compounds is discussed.

代铬刷镀层的耐腐蚀机理的考察

对新型的代铬刷镀层Ｎｉ－Ｆｅ－Ｗ－Ｐ－Ｓ进行了耐腐蚀性能机理的分析研究。用扫描电镜（ＳＥＭ）、透射电镜（ＴＥＭ）、扫描隧道显微镜（ＳＴＭ）、Ｘ射线衍射及电子能谱（ＸＰＳ）等的分析表明，基体组织为非晶结构是代铬刷镀层优异耐腐蚀性的主要原因。

Preparation of tungsten disulfide motor oil and its tribological characteristics

Through using mineral oil and synthetic oil to deploy the semisynthesis base oil, modifying the surfaces of ultrafine tungsten disulfide grains by surface chemical embellishment and adsorption embellishment to make them suspended steadily in the base oil as solid lubricating additive, and adding some function additives, the tungsten disulfide motor oil was prepared. The tribological characteristics of this kind motor oil and the well-known motor oils in our country and overseas were studied. The results show that the oil film strength of this kind of motor oil is respectively 1.06 and 1.38 times of that of shell helix ultra motor oil and great wall motor oil, and its sintering load is 1.75 and 2.33 times of that of them, and when tested under 392 N, 1 450 r/rain and 30 min, the friction coefficients of friction pairs lubricated by the tungsten disulfide motor oil decrease with the increase of time, meanwhile, the diameter of worn spot is small, and the surface of worn spot is smooth, and no obvious furrows appear. The experiments indicate that the tungsten disulfide motor oil has the better antiwear, antifriction and extreme pressure properties than the well-known motor oils.

Field controllable electronic properties of MnPSe_(3)/WS_(2) heterojunction for photocatalysis

Transition metal dichalcogenides are interesting candidates as photocatalysts for hydrogen evolution reaction.The MnPSe_(3)/WS_(2) heterostructure is hence studied here with first principles calculations by exploring its electronic properties under the application of an electric field.It is discovered that the band gap will decrease from the WS_(2) monolayer to the MnPSe_(3)/WS_(2) heterostructure with Perdew-Burke-Ernzerhof functional,while increase slightly when electron correlation is involved.The conduction band minimum of the heterostructure is determined by the MnPSe3 layer,while the valence band maximum is contributed by the WS_(2)layer.The band edges and band gap suggest that the heterostructure will have good photocatalytic properties for water splitting.Moreover,comparing to monolayer WS_(2),the light absorption in both the ultraviolet and visible regions will be enhanced.When an electric field is present,a linear relation is observed between the electric field and the band gap within specific range,which can thus modulate the photocatalytic performance of this heterostructure.

Pressure leaching of bismuth sulfide concentrate containing molybdenum and tungsten in alkaline solution

The leaching results of bismuth sulfide concentrate containing molybdenum and tungsten in air-H2O2-NaOH system, pressure-O2-Na2CO3 system and pressure-O2-NaOH system were investigated. The results show that the extraction of molybdenum, tungsten and sulfur goes up with the increase of NaOH concentration, oxygen partial pressure and reaction time. The extraction of molybdenum and tungsten also rises up with temperature, but the leaching ratio of sulfur increases initially to a peak of 98% at 150℃ and then decreases with the increase of temperature. Under the optimal conditions, the extraction of molybdenum, tungsten and sulfur is more than 95.6%, 93.8% and 96.0%, respectively, and the main phases of residue are Bi2O3 and Fe2O3. Therefore, the method of pressure leaching in alkaline solution is provided as an effective separation of molybdenum, tungsten and sulfur from bismuth and a beneficial pretreatment for consequent process.

Oxidative Desulfurization of Diesel Fuel with Hydrogen Peroxide Using Na_2WO_4 as Catalyst

Oxidative desulfurization was performed on Na2WO4 catalyst in the presence of hydrogen peroxide and acetic acid under mild reaction conditions （atmospheric pressure and temperature range of 293--343 K）. Different organic compounds including benzothiophene （BT）, dibenzothiophene （DBT）, 4, 6-dimethyl dibenzothiophene （4, 6-DMDBT） were used to investigate the reactivity of this catalyst, and the effect of various parameters, such as temperature, solvents and the amount of oxidant reagent used in oxidative desulfurization reaction, was also examined. The results showed that the Na2WO4- H202 system was very effective for oxidative desulfurization, and the oxidation of BT, DBT and 4, 6-DMDBT was influenced by different parameters.

Synthesis,Structure and Reaction of a New BitungstenCompound:(Et_4N)_2W_2S_4 (tdt)_2

The new binuclear tungsten compound (Et4N)2W2S4(tdt)2 (H2tdt=H2S2C6H3CH3) (I) with Mr=1067. 97 has been prepared and characterized by IR andX-ray single crystal analysis. Compound (I) has been synthesized by two routes, ofwhich one was from the reaction of (NH4)WS4 with H2tdt, and the other is from lig-and substitution reaction of W2S4 (dip)2 by H2tdt. The compound contains a typical[W2S4j2+ moiety with a W-W bond of 2. 862(2) A. Its crystallographic data are: or-thorhombic, space group Pbca, a=23. 995 (9), b=31. 496 (7), c=10. 537 (5) A, V=7950(8) A3, Z=8, Dc= 1. 78 g·cm-3, p(MoKa)= 63. 37 cm-1 and R=0. 062 for1926 reflections with I≥3d(I). Synthesis, structure and reaction of the compound arediscussed in this paper.

The Synthesis and Crystallographic Characterization of Heterotrimetallic Linear Complex of [Et_4N][ (Ph_3P)_2{CuS_2WS_2Fe} Br_2]

The complex [Et4N][(Ph3P)2{CuS2WS2Fe} Br2] (1 ), C44, H50NBr2CuFeP2S4W, M4= 1246. 13, has been obtained by reaction of [Et4N]2[WS4] andFeBr2 with Cu (Ph3P )3I in MeCN/CH2Cl2. Crystal data for [Et4N][(Ph3P)2{CuS2WS2Fe) Br2] (1): triclinic, P1, Z = 2, a= 13. 495 (7), b = 15. 322 (5), c =12. 361 (4), a=105. 32(3), β=93. 19(4), γ=101. 35(4) and V=2401. 2 The bond lengths of W-Fe bond and the W-Cu distance are 2. 793(2) A and 2. 823(2), respectively. Three kind metal atoms of the title structure [Et4N][(Ph3P)2{CuS2WS2Fe}Br2] (1) are nearly distributed along a line, and along which three metalatoms (W, Cu, Fe) are approximately tetrahedral coordination.

Covalent functionalization/polycarboxylation of tungsten disulfide inorganic nanotubes （INTs-WS2）

Inorganic nanotubes of tungsten disulfide （INTs-WS2） are insoluble in common solvents and practically inert, hindering their usefulness in both research and commercial applications. The covalent attachment of functional species onto the surface of INT-WS2 is a critical first step in realizing the potential that INT-WS2 offer for high-performance materials and products. Although a few attempts have been reported regarding preparing modified nanotubes, only a limited range of surface functionalities is possible with these methods. We have developed a versatile method, based on a modified, highly electrophilic acidic Vilsmeier- Haack reagent, to produce covalently bonded, polycarboxylated functional WS2 nanotubes that are dispersible in polar liquids, including water. The surface polycarboxylated shell provides a means for additional derivatization, enabling matching compatibility of derivatized nanotubes to both hydrophobic and hydrophilic materials. Nanocomposites incorporating derivatized INT-WS2 are expected to show improved properties as a result of enhanced interfacial compatibility, made possible by the large number of classes of functionalization available through the initial polycarboxylation step.