原位拉曼技术研究Mo催化剂的还原和硫化

运用原位激光拉曼技术研究了Mo/Al_2O_3和Mo/TiO_2-Al_2O_3催化剂的氢还原和硫化行为．结果清楚显示，两种载体上不同配位形态的Mo物种的氢还原能力有明显差异，其硫化性能也不相同．TiO_2对Al_2O_3表面的复盖可显著促进Mo物种的还原和硫化。     

MoS_3 loaded TiO_2 nanoplates for photocatalytic water and carbon dioxide reduction

Photocatalytic water splitting and carbon dioxide reduction provide us clean and sustainable energy resources. The carbon dioxide reduction is also the redemption of the greenhouse effect. MoS_3/TiO_2 photocatalysts based on TiO_2 nanoplates have been synthesized via a hydrothermal acidification route for water and carbon dioxide reduction reactions. This facile approach generates well dispersed Mo S3 with low crystallinity on the surface of TiO_2 nanoplates. The as-synthesized MoS_3/TiO_2 photocatalyst showed considerable activity for both water reduction and carbon dioxide reduction. The thermal treatment effects of TiO_2 , the loading percentage of MoS_3 and the crystalline phase of TiO_2 have been investigated towards the photocatalytic performance. TiO_2 nanoplate synthesized through hydrothermal reaction with the presence of HF acid is an ideal semiconductor material for the loading of MoS_3 for photocatalytic water and carbon dioxide reduction simultaneously in EDTA sacrificial solution.     

固相配位化学反应研究LXVII．金属铜表面M－S（M＝Mo，W）簇合物膜的组成

采用ＦＴＩＲ、ＸＰＳ和ＡＥＳ研究了金属铜表面Ｍ－Ｓ（Ｍ＝Ｍｏ，Ｗ）簇合物膜。结果表明，Ｍｏ（Ｗ）与铜表面的Ｃｕ＿２Ｏ反应，形成了Ｍｏ（Ｗ）－Ｓ－Ｃｕ键；簇合物膜由Ｍｏ（Ｗ）、Ｓ、Ｃｕ、Ｏ元素组成，分别呈＋６、－２、＋１、－２价，膜为多分子层结构并保持ＭｏＳ＿４，或ＷＳ＿２单元，膜表面只有Ｃｕ、Ｏ而不存在Ｍｏ（Ｗ）、Ｓ．膜层厚度与反应时间有关，时间越长，膜越厚。膜为多组分的复杂体系，其颜色是各组分统计分布的结果。     

含固氮酶钼微环境结构单元O_3MoS_3的Mo－S，Mo－Fe－S化合物的研究

研究了含固氮酶钼微环境Ｏ_３ＭｏＳ_３结构单元四个系列化合物［Ｍｏ（Ｓ，Ｏ－Ｃ_６Ｈ_４－１，２］~－（Ｍ）［Ｍｏ_２（ＣＯ）_３（Ｓ，Ｏ－Ｃ_６Ｈ_４－１，２）_３］~（２－）（Ｄ），［Ｍｏ_３（ＣＯ）_７（Ｓ，Ｏ－Ｃ_６Ｈ_４－１，２）_３］~（２－）（Ｔ），和［Ｍｏ_２Ｆｅ（ＣＯ）_４（Ｓ，Ｏ－Ｃ_６Ｈ_４－１，２）_３Ｃｌ_２］~（２－）（Ｔ_ｆ）的合成化学与结构化学，并通过Ｘ－射线光电子能谱，红外光谱和电化学环伏安研究，深入探讨了它们的混合价，电子迁移和电化学行为，也讨论了有趣的Ｏ_３ＭｏＳ_３结构单元。     

Investigation on the active phase of CoMo catalyst for selective HDS by low temperature in situ FT-IR

The CoMo/Al₂O₃ catalysts with different metal loading were studied by low temperature in situ FT-IR using CO as probe molecule which appears to be a powerful method by giving rise to signals specific for unpromoted and promoted Mo sites.The result revealed that the increase of CoMoS phase on the catalyst surface improves the HDS activity and selectivity.The ratio of active site number of CoMoS and MoS₂ correlates linearly with HDS selectivity,which provides an effective tool for developing industrial selective HDS catalysts.     

Grain Boundary Effects on the Mobility of Chemical Vapor Deposition Synthesized Monolayer MoS_2-FETs

Molybdenum disulphide (MoS_2) has emerged as a promising candidate for low-power digital applications.However,grain boundaries play a decisive role in determining the carrier mobility and performance of MoS_2-FETs.In this work,we report a systematic study on the grain boundary of chemical vapor deposition (CVD)MoS_2.We found that in the ON-state,if current flows across a grain boundary that is aligned perpendicular to the channel length,the current of CVD MoS_2-FETs can be significantly reduced,while in the OFF-state,the effect is negligible.Metal-insulator-transition is clearly observed,indicating the high quality of our CVD samples,and it is also shown that grain boundaries increase the metal-insulator-transition crossover-voltage in MoS_2-FETs.Thereby,this work provides useful information and guidance in understanding the nature of carrier transport in synthesized MoS_2 devices,and the developed framework can be applied to other 2D semiconductors in general,as well as in optimizing the CVD process and device design with 2D materials.     

In-situ TEM investigation of MoS_2 upon alkali metal intercalation

Phase transition in two dimensional molybdenum disulfide (MoS_2) can be induced by several methods and has been investigated for decades. Alkali metal insertion of MoS_2 had been proved an effective method to cause phase transition early in 1970s, and has been gaining renewed interest recently, due to the possible application of MoS_2 in energy storage. The alkali metal intercalation of MoS_2 has been studied by various techniques, among which in-situ transmission electron microscopy (TEM) provides unique capability of real time resolving the structural evolution of the materials at high spatial resolutions. Here by in-situ TEM technique we investigated the structural evolution of MoS_2 upon lithium and sodium intercalation, along with transformation of the nanosheet and variation of the electron diffraction patterns. The intercalation process is accompanied by emergence of superstructures, which exist in several forms. The ion intercalation results in phase transition of MoS_2 from 2H to 1T, and the driving mechanism of the phase transition are discussed. The work provides a more comprehensive understanding of ion intercalation induced phase transition of MoS_2.     

Self-assembled Nanohybrid from Opposite Charged Sheets: Alternate Stacking of CoAl LDH and MoS_2

Hybrid materials are attracting intensive attention for their applications in electronics, photoelectronics, LEDs, field-effect transistors, etc. Engineering new hybrid materials and further exploiting their new functions will be significant for future science and technique development. In this work, alternatively stacked self-assembled CoAl LDH/MoS_2 nanohybrid has been successfully synthesized by an exfoliation-flocculation method from positively charged CoAl LDH nanosheets(CoAl-NS) with negatively charged MoS_2 nanosheets(MoS_2-NS). The CoAl LDH/MoS_2 hybrid material exhibits an enhanced catalytic performance for oxygen evolution reaction(OER) compared with original constituents of CoAl LDH nanosheets and MoS_2 nanosheets. The enhanced OER catalytic performance of CoAl LDH/MoS_2 is demonstrated to be due to the improved electron transfer, more exposed catalytic active sites, and accelerated oxygen evolution reaction kinetics.     

水热法合成MOS2/CNT同轴纳米管

采用水热法合成了MoS2/CNT同轴纳米管．对合成的MoS2/CNT同轴纳米管用高分辨透射电镜(HRTEM)、X射线衍射(XRD)和电子能谱(EDS)方法对其进行了鉴定和表征,发现所制备的MoS2/CNT同轴纳米管结构完好,在CNT的外表面包覆了3～4层MoS2管．初步分析了MoS2/CNT的形成机理．     

硫化的MoO3/γ—Al2O3催化剂的表面结构和价态的研究

本文应用XPS、ESR和TEM等手段研究了硫化的MoO_3/γ-Al_2O_3催化剂样品, 在不同钼含量、不同硫化条件以及进行甲烷反应前后, 其表面结构和价态的变化规律。观察到硫化时Mo~(+6)。还原为Mo~(+5)和Mo~(+4)的变化过程。硫化除了生成S~(-2)价态外, 还有硫的高价中间态生成。证明了经甲烷化反应后, 表面上的MoS_2晶粒明显长大。     

The Co_3O_4 nanosheet array as support for MoS_2 as highly efficient electrocatalysts for hydrogen evolution reaction

The electrochemical hydrogen evolution reaction(HER) on a non-precious electrocatalyst in an alkaline environment is of essential importance for future renewable energy. The design of advanced electrocatalysts for HER is the most important part to reduce the cost and to enhance the efficiency of water splitting. MoS_2 is considered as one of the most promising electrocatalysts to replace the precious Pt catalyst.Herein, for the first time, we have successfully loaded MoS_2 electrocatalysts onto the Co_3O_4 nanosheet array to catalyze HER with a low onset potential of ~76 mV. The high hydrogen evolution activity of MoS_2 supported on the Co_3O_4 nanosheet array may be attributed to the increased active sites and the electronic interactions between MoS_2 and Co_3O_4.     

新型十八核聚氧钼酸盐的合成与结构

合成了新化合物(NH4)6•[Ca2(H2O)6(CH3COO)2]•{Ca@[O52(OH)4(CH3COO)2]}•14H2O，并运用元素分析和单晶X衍射对其结构进行了表征.测定结果证实,该化合物由十八个钼氧八面体相互连接而成，呈现一种有趣的环状结构.在环的中心有一个Ca2＋离子，它通过与环上的四个酰氧配位而与环骨架相连.有十个钼原子呈正六价，而其余八个钼原子呈正五价，且有Mo－Mo键存在.环上还有配位相连的四个乙酸配体.在环的上下各有两个Ca2＋离子，它通过与该环和其它环上的氧原子配位而把环连成一维链状结构.晶体属三斜晶系，空间群P1，晶胞参数：a=1.055 2(2) nm， b=1.515 0(3) nm， c=1.544 9(3) nm， α=60.84(3)， β=88.00(3)， γ=71.21(3)°，V=2.019 4(7) nm3， R1=0.036 6（对可观察点）， wR2=0.083 3（对独立点）.     

丙烯选择氧化反应中钼基催化剂动态结构的研究

 用原位共焦显微拉曼光谱技术考察了丙烷选择氧化反应中Ag－M\r\no－P－O催化剂的结构，讨论了催化剂动态结构的成因及其对催化剂性\r\n能的影响．实验结果表明，在773K和n（C3H8）∶n（O2）∶n（N2）＝\r\n3∶1∶4的反应条件下，Ag－Mo－P－O催化剂中的Mo－O物种可转化为A\r\ngMoO2PO4中的Mo－O物种（多钼酸根），此时催化剂对丙烷选择氧化具\r\n有较高的催化活性．催化剂中Mo－O物种的转化是由MoO3中Mo－O物种和\r\nAgMoO2PO4中Mo－O物种的结构特性决定的．AgMoO2PO4中的Mo－O物种具\r\n有较强的参与MarsvanKrevelen氧化－还原循环的能力，可能是丙烷选\r\n择氧化反应的活性物种．     

Mo(W)-Cu(Ag)-S簇合物的拓扑学研究

本文给出了一种由Mo(W)-Cu(Ag)-S簇合物分子式导出可能结构的拓扑方法。作为例子，文中利用该方法导出了四核单Mo(W)簇合物的各种可能结构，并预测了簇合物［Mo₂O₂S₆Cu₄(PPh₃)₄］的各种可能结构。本文介绍的拓扑方法，为Mo(W)-Cu(Ag)-S簇合物的结构提供了一个组织框架，也为预测簇合物的新结构提供了一个合理的基础和途径。     

Synthesis and Structure of a Dimolybdenum Carbonyl Compound with Thiolato Bridges 〔Et_4N〕_2〔Mo_2(CO)_8(SC_6H_4-Cl-p)_2〕

１　ＩＮＴＲＯＤＵＣＴＩＯＮＳｔｕｄｉｅｓｏｎＭｏ－Ｓ（ＳＲ）ｃｏｍｐｏｕｎｄｓｈａｖｅａｌｗａｙｓｂｅｅｎａｎａｃｔｉｖｅｒｅｓｅａｒｃｈａｒｅａｂｅ－ｃａｕｓｅｏｆｔｈｅｅｘｉｓｔｅｎｃｅａｎｄｉｍｐｏｒｔａｎｃｅｏｆＭｏ－Ｓ（ＳＲ）ｂｏｎｄｉｎｇｉｎｍｏｌｙｂｄｅｎｕｍｅｎ－ｚｙｍｅｓ〔１〕ｉｎｂｉｏｌｏｇｉｃａｌｓｙｓｔｅｍａｎｄｔｈｅｐｏｔｅｎｔｉａｌａｐｐｌｉｃａｔｉｏｎｔｏｍａｔｅｒｉａｌｓａｎｄｃａｔａｌｙｓｔ〔２〕．Ｉｎｒｅｃｅｎｔｙｅａｒｓ,ｗｅａｒｅｉｎｔｅｒｅｓｔｅｄｉｎ…     

Synthesis and Structure of Dimolybdenum Carbonyl Thiolate Compound [Et4N]2[Mo2（CO）8（SC6H4—CH3—m）2]

1 INTRODUCTION In 1984, thiolate ligand was successfully introduced into molybdenum carbonyl compound by the reaction of Mo(CO)6 with [Et4N]SR( R = C6H5, But) in a moderate condition[1]. From then on, a series of dinuclear molybdenum(0) carbonyl thiolate compounds have been synthesized and characterized by using a variety of thiolate ligands in our research group. It was found that a planar Mo2S2 unit is in the compound [Et4N]2[Mo2(CO)8(SC6H4-CH_3-p)2][2] (2) and a "butterfly" t…     

Synthesis and Structures of Two New Molybdophosphates

A one-dimension solid and a two-dimension solid consisting of polyoxoanions bridged by {CoO3N2} and {CoO4} groups respectively have been synthesized by the hydrothermal method and structurally characterized by X-Ray crystallography. Each structure has the [(PO4)4Mo6O15]^12- cluster that is commonly observed in many molybdophosphates. In compound 1, [(PO4)4Mo6O15]^12- clusters are linked by {CoO3N2} groups to form a chain-like structure, and the chains are hydrogen-bonded into a network. Compound 2 is a layer structure with channnels constructed from [(PO4)4Mo6O15]^12- clusters and {CoO4} groups, the organic molecules and the lattice water molecules are distributed disorderly in the interlamellar region and form strong hydrogen bonds with inorganic framework. The IR and the fluorescent spectra were investigated and discussed.     

Synthesis and Structure of Dinuclear Molybdenum Carbonyl Thiolate Compound[Et4N]2[Mo2(CO)8(SC6H4-CH3-p)2]

1　ＩＮＴＲＯＤＵＣＴＩＯＮＳｉｎｃｅｔｈｉｏｌａｔｅｌｉｇａｎｄｗａｓｉｎｔｒｏｄｕｃｅｄｉｎｔｏｍｏｌｙｂｄｅｎｕｍｃａｒｂｏｎｙｌｃｏｍｐｏｕｎｄｉｎ1 984 [1],ｔｈｅｉｎｖｅｓｔｉｇａｔｉｏｎｏｎｌｏｗ ｖａｌｅｎｃｅＭｏ -ＳＲｃｏｍｐｏｕｎｄｓｈａｓｒｅｃｅｉｖｅｄａｔｔｅｎｔｉｏｎｆｏｒｔｈｉｓｋｉｎｄｏｆｌｏｗ ｖａｌｅｎｃｅｃｏｍｐｏｕｎｄｓｐｏｓｓｅｓｓｃｅｒｔａｉｎａｄｖａｎｔａｇｅｏｎｃｏｍｐｏｕｎｄｓｙｎ ｔｈｅｓｉｓ,ｍｏｌｅｃｕｌｅｓｔｒｕｃｔｕｒｅａｎｄｐｈｙｓｉｃａｌａ…     

Determination of the Mo surface environment of Mo/TiO2 catalysts by EXAFS,XANES and PCA

The local structure of oxidic Mo/TiO₂ catalysts (0.5 to 13.5 wt.% Mo) has been studied using EXAFS and XANES. Both EXAFS and XANES results suggest that the Mo surface phase is octahedrally coordinated for all Mo loadings. The EXAFS results were also examined using principal component analysis (PCA) to determine the number of Mo species present on the Mo/TiO₂ catalysts. Results from PCA of the Mo EXAFS spectra suggested the presence of three Mo species: two surface species and bulk MoO₃.     

A New Ionic Trimolybdenum Cluster Compound:〔Mo_3S_7(S_2P(iprO)_2)_3〕〔S_2P(iprO)_2〕

1INTRODUCTIoNInthepastdecades,thechemistryofMo-Sclusterscontaininga[Mo,(p,-S)(p-S,),j corehasbeenstudiedtextensively,andmanysuchkindofcompoundshavebeensynthesized.(1'2'3'4iHowever,fewcompoundscontainingadiscreteclus-tercationhavebeenreported.[5iInthispaper,wereportthesynthesisandstructureofthetitlecompound.Thisisanewexampleoftrimolybdenumclustercontainingadiscreteclustercation.2EXPERIMENTALAllmanipulationwerecarriedoutinair.2.1Synthesis0f[M0,S,(S,P(iprO),),jtS,P(iprO),jAmixture…