Low-temperature catalytic preparation of multi-wall MoS<Subscript>2</Subscript> nanotubes

In the catalytic reduction atmosphere of H₂+CH₄+C₄H₄S, the ball-milled precursor (NH₄)₂MoS₄ is heated to 300°C for decomposition. The as-synthesized product is characterized by XRD, SEM, HRTEM, EDX, and BET. The results show that multi-wall MoS₂ nanotubes are obtained. The length of the nanotubes is around 3–5 μm. The diameters of the nanotubes are homogeneous, with an inner diameter of ∼15 nm, an outer diameter of ∼30 nm, and an interlayer (002) d-spacing of 0.63 nm. This catalytic thermal reaction occurring at low temperatures is important for the large-scale preparation of similar transition-metal disulfide nanotubes.     

MoS2/C复合纳米管的合成

在900℃氢气气氛下,通过热分解载有硫代钼酸铵的碳纳米管前驱物得到MoS₂/C复合纳米管.通过粉末X射线衍射(XRD)、拉曼光谱(Raman)、高分辨透射电镜(HRTEM)和X射线能量散射仪(EDS)等方法对其形貌、结构和成分进行了表征.结果表明,所合成物质是一种由两种材料组成管壁的新型纳米管.     

钛纳米管负载锰催化剂的低温选择性催化还原脱硝性能

采用水热法合成了钛纳米管（TiNT）,以400℃焙烧后得到的TiO₂纳米管为载体,采用浸渍法制备了MnO_x/TiNT催化剂,用于低温NH₃选择性催化还原脱NO反应（SCR）。BET、TEM、XRD及TG测试表明,经过400℃焙烧之后的钛纳米管主要成分为锐钛矿型TiO₂,所制备的催化剂活性组分分散性较好。在模拟烟气条件下,考察了锰负载量、空速、O₂含量、氨氮比及进口NO浓度对MnO_x/TiNT的SCR催化性能的影响。在150℃、\[NH₃\]/\[NO\]比为1.2、O₂浓度为3%、NO浓度为0.06%、空速GHSV为23613.8h^-1、Mn的负载量为5%~15%的条件下,NO的转化率达到95%以上。反应气氛中单独通入水会造成催化剂的活性下降;切断H₂O,催化剂的活性可以恢复至初始水平。温度越高,催化剂抗水性能越好,而且水存在情况下的抗硫性能优于其单独抗硫性能。再次切断H₂O和SO₂,催化剂的活性逐渐上升,但不能恢复到初始水平。     

单个MoS2纳米片氢析出催化特性研究

MoS₂作为高效的电催化氢析出(HER)催化剂已有大量文献报道. 实验和DFT计算结果都表明MoS₂的高氢析出活性来源于边缘,而其基面是催化惰性的。为了进一步验证此结论,本文利用巯基羧酸在恒电位下自组装单层修饰的纳/微米电极固定不同尺寸的单个纳米片状,对MoS₂氢析出催化活性与其尺寸的关系进行研究,发现纳米片状MoS₂具有较高的催化活性,同时较小尺寸的MoS₂氢析出活性更高,说明MoS₂的边缘的增多对其催化活性有巨大提升,即证明了边缘部分具有更高的氢析出催化活性.     

以聚乙二醇为模板剂制备MoS2空心微球

以聚乙二醇(PEG)为模板剂,采用软模板法制备出MoS2空心微球,并采用X射线衍射仪(XRD)、红外光谱仪(IR)和扫描电子显微镜(SEM)对产物进行表征.结果表明,所制备的MoS2为粒径约2-7μm的空心微球,但结晶程度较差,需通过退火工艺进行改善;聚乙二醇与MoS2发生了较为强烈的有机-无机杂化作用,其浓度和分子量对产物形貌调控均有重要影响.同时,结合红外光谱分析,对MoS2空心微球的形成机理进行了初步的探讨.     

铁基粉末冶金材料中稀土元素与MoS2的交互作用研究

通过实验研究了添加到铁基粉末冶金摩擦材料中的稀土在材料中存在的位置和状态以及稀土对MoS2分解所产生的影响.电子探针检测的结果表明, 稀土在铁基粉末冶金磨擦材料中主要集中分布于孔隙处, 且其分布呈聚集的粒状, 常与Pb等重金属共存; 稀土有强烈的促进MoS2分解的作用, 当加入量超过3倍单位量时即可使加入的4%(质量分数)的MoS2完全分解.     

碳纳米管预处理及其在催化材料中应用

本文以碳纳米管作催化剂载体为出发点,回顾了大管径尤其是大内径碳纳米管制备,介绍了不同纯化处理工艺对碳纳米管性能的影响,综述了制备、预处理等因素对碳纳米管复合材料和碳纳米管负载型催化剂性能的影响。     

水热法合成MOS2层状材料及其结构表征

以硫脲为还原剂和硫源,利用水热法在160～220℃下反应,合成了具有很好晶相的MoS2．采用XRD,XPS和TEM对其进行了结构表征,比较了反应温度对于成晶的影响,并且讨论了反应机理．研究表明,用此种方法合成MoS2较以往的水热合成所用时间短,温度低,获得的晶相好,同时还有效地避免了使用吡啶等有机溶剂所带来的污染,为合成其他过渡金属硫化物提供了新途径．     

Cobalt-promoted MoS2 nanosheets: A promising novel diesel hydrodesulfurization catalyst

MoS₂ has been commonly used as a catalyst in hydrodesulfurization (HDS) of petroleum cuts in crude oil refineries. In this study, the synthesis of unsupported MoS₂ and Co-promoted MoS₂ nanosheets produced from molybdenum oxide and thiourea is reported. The synthesized samples were characterized by using x-ray fluorescence, x-ray diffraction, Brunauer–Emmett–Teller (BET), temperature-programmed reduction, thermal gravimetric analysis, and transmission electron microscopy methods, and then they were utilized for HDS of diesel through a fixed-bed catalytic reactor. Results indicated that a cobalt promoter affected both the number and the performance of active sites of the molybdenum sulfides, and the activity of the promoted MoS₂ catalyst was consistently higher than that of the MoS₂ catalyst. More significantly, the activity of the promoted catalyst was slightly declined during 48 h continuous HDS reaction, which indicated the stability of this catalyst. Additionally, during 12 h of test run, the HDS activity of the promoted catalyst was about 60% higher than MoS₂ one.     

Covalent Patterning of 2D MoS2

The development of an efficient method to patterning 2D MoS₂ into a desired topographic structure is of particular importance to bridge the way towards the ultimate device. Herein, we demonstrate a patterning strategy by combining the electron beam lithography with the surface covalent functionalization. This strategy allows us to generate delicate MoS₂ ribbon patterns with a minimum feature size of 2 μm in a high throughput rate. The patterned monolayer MoS₂ domain consists of a spatially well-defined heterophase homojunction and alternately distributed surface characteristics, which holds great interest for further exploration of MoS₂ based devices.     

高比表面积TiO_2纳米管的制备与表征

采用一种简单的化学合成方法制备TiO2 纳米管 ,并采用TEM、XRD等分析手段对TiO2 纳米管进行了表征 .考察了不同温度对TiO2 纳米管比表面积及孔体积的影响 .结果表明 ,采用该方法制得的TiO2 纳米管 ,比用模板法制备的TiO2 纳米管的管径小、管形均匀 .此纳米管的比表面积大于 2 0 0m2 /g ,孔体积最大可达 0 .784cm3 /g .     

Enhanced Thermal Decomposition Properties and Catalytic Mechanism of Ammonium Perchlorate over CuO/MoS2 Composite

In this report, CuO/MoS₂ composites were successfully prepared by the hydrothermal method where nano‐sized CuO was uniformly distributed on the surface of hierarchical MoS₂ substrates (CuO/MoS₂ composites). Their physicochemical properties and catalytic performance in ammonium perchlorate (AP) decomposition were investigated and characterized by XRD, SEM, TEM, BET, XPS, TG/DSC and combustion measurement. The results showed that it could decrease AP decomposition temperature at high decomposition stage from 416.5 °C to 323.5 °C and increase the heat release from 378 J/g (pure AP) to 1340 J/g (AP with catalysts), which was better than pure CuO nanoparticles (345.5 °C and 1046 J/g). Meanwhile, it showed excellent performance in combustion reaction either in N₂ or air atmosphere. The results obtained by photocurrent spectra, photoluminescence spectra and time‐resolved fluorescence emission spectra indicated that loading CuO mediated the generation rate and combination rate of electrons and holes, thus tuning the catalytic performance on AP decomposition. This study proved that employing the supports that can synergistically interact with CuO is an efficient strategy to enhance the catalytic performance of CuO.     

MoS2的水热合成及其润滑性能

利用水热合成法在相对较低的反应温度(200 ℃)和较短的反应时间(24 h)内合成了MoS2.采用透射电子显微镜(TEM)、X射线光电子能谱(XPS)和X射线衍射(XRD)分析了合成的纳米MoS2的结构.同商品MoS2（平均颗粒直径为3～5 μm）进行了摩擦学性能对比，并利用俄歇电子能谱(AES)深度剖析和XPS分析了MoS2作为润滑剂在钢磨损表面的粘着成膜作用及润滑机理.结果表明,该水热合成的产品具有较商品MoS2更低的摩擦系数，适合在大载荷、长时间工作状况下使用.     

The influence of melamine phosphate modified MoS2 on the thermal and flammability of poly(butylene succinate) composites

This work reported a facile fabrication method to modify molybdenum disulfide (MoS₂) nanosheets with common flame retardant melamine phosphate (MAP) and then were incorporated into poly(butylene succinate) by melt blending method with the purpose of improving the thermal and flame retardancy properties. MAP modified MoS₂ nanosheets dispersed well in poly(butylene succinate) composites with intercalated structure. The incorporation of MAP modified MoS₂ nanosheets led to an increase of thermal degradation temperature and char formation as well as reduction of the peak heat release rate. Copyright © 2016 John Wiley & Sons, Ltd.     

MoS_2纳米片及其增强环氧树脂基复合材料的制备与性能研究

以液相分散法为基础制备了MoS2纳米片悬浮液.对该悬浮液进行了吸光性能和荧光性能表征;结果显示悬浮液荧光信号明显增强;同时得到增加超声时间、降低离心转速、采用粒径较大的块状粉末和加入球磨工艺这些因素是可以提高悬浮液的吸光度的优化工艺条件.采用微区荧光测试测得了单个MoS2纳米片的荧光光谱,其主峰位置在652 nm,对应的带隙能量是1.9 e V;还对单个纳米片进行退火处理,其荧光信号在退火后有所增强.对MoS2纳米片进行了AFM和SEM表征显示大部分纳米片的平面尺寸在几百纳米,厚度约为几纳米.另外,将MoS2纳米片悬浮液与E51环氧树脂混合,制备了MoS2纳米片增强环氧树脂基复合材料.对该复合材料进行了荧光性能和拉伸性能测试.结果显示复合材料的荧光信号也明显增强;且经退火后,因为复合材料内部残余热应力的关系,该复合材料的荧光信号的峰值位置出现移动.同时,该复合材料的韧性也有提升.     

金纳米粒子修饰的三维花状二硫化钼复合材料的制备及其用于检测过氧化氢的研究

以Na_2MoO_4·2H_2O为钼源,硫脲为硫源和还原剂,氧化多壁碳纳米管(o-MWNTs)和氧化石墨烯(GO)为原料,采用水热法合成了三维花状MoS_2/GO/o-MWNTs纳米复合材料,并进一步采用原位还原法将金纳米粒子修饰至MoS_2/GO/o-MWNTs纳米复合材料表面。通过场发射扫描电镜、透射电镜、XRD、XPS等对上述复合材料进行表征。结果表明,该复合纳米材料具有3D花状球结构,且Au纳米粒子已成功生长在其花瓣状片层上。采用滴涂法制得该复合材料修饰的玻碳电极,研究了过氧化氢在该电极上的电化学行为。结果表明:该电极对过氧化氢的电还原表现出强催化活性。通过对不同浓度过氧化氢的催化还原,得出该电极对过氧化氢的线性范围为12.0×10~(-9)～31.0×10~(-6) mol/L,灵敏度为56.6μA/(mmol·L~(-1)),检出限为12.0×10~(-9) mol/L。     

Preparation of Nanocrystalline MoS2 Hollow Spheres

NanocrystaUine MoS2 with hollow spherical morphology has been prepared by the hydrothermal method. The products are characterized by means of X-ray powder diffraction,transmission electron microscopy and high-resolution transmission electron microscopy. The experimental results give the evidence that the sample is consists of hollow spheres 400～600nm in diameter, and there is much whisker on the surface of MoS2 hollow sphere.     

Fe—Co双金属催化剂对纳米碳管规模化生产的影响

在C2H2和N2的氛围下,以Fe－Co双金属氧化物为催化剂,利用催化裂解法大量制备了多壁纳米碳管,实验结果表明,以Fe－Co双金属氧化物为催化剂制备纳米碳管的产量明显高于Fe或Co单独存在时所得的纳米碳管的产量,且Fe摩尔分数为0.2时效果最佳;同时发现,在制备的产品中存在很多螺旋形的纳米碳管,此方法工艺简单,有利于纳米碳管的规模化、大批量生产,为纳米碳管的深入研究及广泛应用打下了基础。     

Tuning the Photo-electrochemical Performance of RuII-Sensitized Two-Dimensional MoS2

Covalently tethering photosensitizers to catalytically active 1T-MoS₂ surfaces holds great promise for the solar-driven hydrogen evolution reaction (HER). Herein, we report the preparation of two new Ru^II-complex-functionalized MoS₂ hybrids [Ru^II(bpy)₂(phen)]-MoS₂ and [Ru^II(bpy)₂(py)Cl]-MoS₂. The influence of covalent functionalization of chemically exfoliated 1T-MoS₂ with coordinating ligands and Ru^II complexes on the HER activity and photo-electrochemical performance of this dye-sensitized system was studied systematically. We find that the photo-electrochemical performance of this Ru^II-complex-sensitized MoS₂ system is highly dependent on the surface extent of photosensitizers and the catalytic activity of functionalized MoS₂. The latter was strongly affected by the number and the kind of functional groups. Our results underline the tunability of the photovoltage generation in this dye-sensitized MoS₂ system by manipulation of the surface functionalities, which provides a practical guidance for smart design of future dye-sensitized MoS₂ hydrogen production devices towards improved the photofuel conversion efficiency.     

新型二元相MoS2/C纳米管的合成和机理研究

在900 ℃氢气气氛下, 通过热分解载有硫代钼酸铵的碳纳米管前驱物得到MoS₂/C二元相纳米管. 通过粉末X射线衍射(XRD)、高分辨透射电镜(HRTEM)、扫描电镜(SEM)和X射线能量散射仪(EDS)等方法对其形貌、结构和成分进行了表征. 结果表明, 我们合成了一种由两种材料组成管壁的新型纳米管, 并对其形成机理进行了研究.