含US—SSY分子筛的Ni—W—γ—Al2O3体系的EXAFS研究

运用ＥＸＡＦＳ技术分别对含有自冷和急冷ＵＳ－ＳＳＹ分子筛的Ｎｉ－Ｗ－γ－Ａｌ２Ｏ３样品中的Ｗ和ＬⅢ吸收边的Ｎｉ的Ｋ吸收边进行了结构分析。结果表明分子筛超稳化后的冷却速率对样品中原子的局域结构有影响，进而影响了样品的催化活性。急冷样品中Ｗ的分散度比自冷样品差，其八面体结构含量较高，并有钨钼氧原子簇产生。     

EXAFS研究加氢处理催化剂载体中Y型分子筛对催化性能的影响

运用广延X射线吸收精细结构技术对经Y型分子筛改性前、后的加氢处理催化剂Ni W γ Al2 O3样品的W的LⅢ吸收边和Ni的K吸收边进行了结构分析。结果发现 ,经Y型分子筛改性后的催化剂Ni W γ Al2 O3体系中活性组分Ni和W的局域原子环境有所变化 :催化剂中组分的八面体结构变得松散 ,W—O键较弱 ,O易于在加氢脱硫反应中被替代 ,而催化剂表面金属Ni组分浓度略有增加 ,这些变化有利于提高催化剂的加氢脱硫能力     

CO_2甲烷化Ni基分子筛催化剂的研究进展

综述了镍基分子筛催化剂在CO_2甲烷化反应中的研究进展,系统总结了不同分子筛催化剂对CO_2甲烷化反应性能的影响,分析了不同分子筛载体结构与活性组分之间的相互作用及其对活性组分Ni的分散度、颗粒尺寸、抗烧结性之间的关系,阐释了不同孔结构分子筛催化剂的构效关系及其抗烧结和抗积碳的反应机理,展望了Ni基分子筛催化剂在甲烷化反应的应用前景。     

EXAFS研究和加氢处理催化剂载体中Y型分子筛对催化性能 …

运用广延Ｘ射线吸收精细结构技术对经Ｙ型分子筛改性前、后的加氢处理催化剂Ｎｉ－Ｗ－γ－Ａｌ２Ｏ３样品的Ｗ的ＬⅢ吸收边和Ｎｉ的Ｋ吸收边进行了结构要现,经Ｙ型分子筛改性后的催化剂Ｎｉ－Ｗ－γ－ＡｌＯ３体系中活性组分Ｎｉ和Ｗ的局域原子环境有所变化：催化剂中组分的八面体结构变得松散,Ｗ－Ｏ键较弱,Ｏ易于在加氢脱硫反应中被替代,而催化剂表面金属Ｎｉ组分浓度略有增加,这些变化有利于提高催化剂的加氢脱硫能力。     

小样品快速冷却实验台的研制及应用

研制了一种用于小样品在低温冷却介质中实现超快速冷却的实验台。通过该实验台对小样品实施弹射,其弹射速度在较宽范围内可调,同时能对小样品的沉浸速度和淬冷温度进行准确的测量。将其应用于小样品在过冷液氮中的超快速冷却过程,可以实现较高的沉浸速度和冷却速率。实验研究表明随着小样品沉浸速度的增大、液氮过冷度的增加,冷却速率明显增加。     

负载含银介孔分子筛活性碳纤维的制备与性能

将CAF加入由以十二胺，正硅酸乙酯，乙醇，水等组成的介孔分子筛（MS）合成反应液中制备负载MS的活性碳纤维（ACF－MS），MS含量由反应液中ACF的含量确定，通过真空浸渍和热分解使ACF－MS载银，载成新型净水材料－负载含银介孔分子筛的活性碳纤维（ACF－MS（Ag)），银含量由浸渍时间控制，在流动水的冲刷下ACF－MS（Ag)样品中的银含量缓慢下降，下降速率随着水流速和样品含银量的增加而增加，与ACF（Ag）相比，ACF－MS（Ag)的耐水冲刷性能显著提高。     

表面高氨基官能化介孔SBA－15分子筛的制备

文章报道了一种利用甲苯二异氰酸酯（TDI）作桥连分子制备高氨基官能化介孔SBA－15分子筛的方法。首先,SBA－15表面的Si－OH与TD1分子中的一个－NCO基反应,然后,TD1分子中另一端未参与反应的－NCO基与乙二胺分子中的一个－NH2基反应,如此,－NH2被成功地嫁接到介孔SBA－15分子筛表面,用XRD、N2－吸脱附、FTIR和^29Si MA SNMR表征,结果表明,一NH2被成功引入到SBA－15分子筛表面,且材料具有良好的介孔结构。     

热镀Ni3Al耐蚀合金镀层液态冷凝过程的分子动力学模拟研究

钢铁表面热镀Ni3Al耐蚀合金过程中，涉及Ni3Al合金在钢铁表面由液态冷凝为镀层，冷却速度对结构及性能影响很大。采用F－S多体势对耐蚀液态合金Ni3Al在不同冷却速度下的微观结构及其转变机制进行了分子动力学模拟，得到了不同冷速下各温度的双体分布函数；采用HA键型指数法对其结构进行了分析，结果表明：Ni3Al的结构及能量转变受冷速影响较大，快冷时形成非晶，而慢冷时出现明显结晶，晶体的形成过程中有能量突变。     

Ti—B超硬薄膜的合成及其显微结构和显微硬度的研究

采用离子束增强沉积方法，在ｐ型单晶硅衬底上，通过不同能量的氙离子辅助轰击，以不同的沉积速率制备了Ｔｉ－Ｂ超硬薄膜。Ｘ射线衍射分析结果表明，Ｔｉ－Ｂ薄膜呈ＴｉＢｘ多晶结构，其晶化程度蒸发速率的不同而变化，而其缺位值ｘ随氙离子轰击能量的不同而变化。     

焙烧温度对CuO在γ-Al2O3载体上的分散和催化CO完全氧化性能的影响

采用浸渍法制备了经不同温度焙烧的CuO/γ-Al2O3催化剂,并通过BET、XRD、UV-DRS、H2-TPR以及CO完全氧化反应,研究了不同焙烧温度对CuO/γ-Al2O3催化剂中CuO组分的分散、还原和催化性质的影响.结果表明:当焙烧温度为450℃时,CuO在γ-Al2O3上的分散容量约为0.56mmol/100m2;当焙烧温度达到750℃时,Cu2 同时占据γ-Al2O3载体(110)面上的八面体和四面体空位.对于450℃焙烧的低CuO含量的样品,在H2-TPR结果中只观察到处于八面体空位的CuO物种的还原,而经750℃焙烧的样品则同时观察到处于八面体和四面体空位的CuO物种的还原,且处于八面体空位的CuO的还原会促进处于四面体空位的CuO的还原.处于八面体空位的CuO在CO完全氧化反应中的活性要高于处于四面体空位的CuO.     

Carbon-Doped Nickle Via a Fast Decarbonization Route for Enhanced Hydrogen Oxidation Reaction in Alkaline Media

Nickel (Ni) based materials with non-metal heteroatom doping are competitive substitutes for platinum group catalyst toward alkaline hydrogen oxidation reaction (HOR). However, the incorporation of non-metal atom into the lattice of conventional fcc phase Ni can easily trigger a structural phase transformation, forming hcp phase nonmetallic intermetallic compounds. Such tangle phenomenon makes it difficult to uncover the relationship between HOR catalytic activity and doping effect on fcc phase Ni. Herein, taking trace carbon doped Ni (C-Ni) nanoparticles as an example, a new nonmetal doped Ni nanoparticles synthesized by a simple fast decarbonization route using Ni₃C as precursor is presented, which provides an ideal platform to study the structure-activity relationship between alkaline HOR performance and non-metal doping effect toward fcc phase Ni. The obtained C-Ni exhibits an enhanced alkaline HOR catalytic activity compared with pure Ni, approaching to commercial Pt/C. X-ray absorption spectroscopy confirms that the trace carbon doping can modulate the electronic structure of conventional fcc phase nickel. Besides, theoretical calculations suggest that the introducing of C atoms can effectively regulate the d-band center of Ni atoms, resulting in the optimized hydrogen absorption, thereby improving the HOR activity.     

Ni／CNTs及钙改性Ni／CNTs催化剂在二氧化碳甲烷化反应中性能

分别以碳纳米管（CNTs）和活性氧化铝（Al2O3）为载体,通过浸渍法制备了负载型镍基催化剂和钙改性的镍基催化剂,用二氧化碳甲炕化反应评价其催化性能,通过X射线衍射（XRD）、程序升温还原（H2-TPR）、程序升温脱附（H2-TPD）和氮气等温吸附脱附等手段对催化剂进行表征,结果表明,Ni／CNTs催化剂中的镍物种比Ni／Al2O3中的镍物种容易还原,同时钙改性Ni／CNTs催化剂更能促进镍物种的还原,添加钙可以促进CNTs载体催化剂的分散度,这些特性能提高钙改性Ni／CNTs催化剂的催化活性和稳定性。     

Hydrodesulphurisation activity of CoMo catalyst supported on multi wall carbon nanotube: sulphur species study

Multi wall carbon nanotube (MWCNT) supported CoMo catalyst was prepared and hydrodesulphurisation (HDS) activity of naphtha was evaluated in a fixed bed down flow reactor. Activity test experiments were conducted at a temperature of 310°C, pressure of 15?bar and liquid hourly space velocity of 4/h. The conditions were close to those of industrial practice. The structure of the MWCNT was investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and accelerated surface area and porosity system (ASAP). The catalyst was characterised by X-ray diffraction, SEM, energy dispersive X-ray, inductively coupled plasma optical emission spectrometry, TEM and ASAP. Also for sulphur species study, naphtha feed and product were analysed by gas chromatography–sulphur chemiluminescence detection. Catalytic activity test indicated that MWCNT is a suitable support for HDS catalyst. Sulphur conversion of the catalyst was 88%. Also sulphur species comparison showed that all the sulphur types were converted.     

磷改性Ni/MoS_2复合材料的制备及其催化性能

在超声波作用下,采用单分子层剥离-重堆技术,正丁基锂柱插MoS2夹层,合成了前驱体LixMoS2和磷(P)改性Ni/MoS2复合材料,以二苯并噻吩、喹啉催化加氢为探针反应,考察了其催化活性.实验结果表明,P改性Ni/MoS2催化剂具有很强的加氢脱硫、脱氮活性和选择性,P元素的最佳添加量为2.05%,二苯并噻吩、喹啉的转化率分别达到了98.2%、99.8%.XRD、FT-IR、ICP-EDS、BET的分析检测,揭示了P改性Ni/MoS2催化剂的微观结构和内在规律性.     

Ganoderma‐Like MoS2/NiS2 with Single Platinum Atoms Doping as an Efficient and Stable Hydrogen Evolution Reaction Catalyst

Herein, a unique ganoderma‐like MoS₂/NiS₂ hetero‐nanostructure with isolated Pt atoms anchored is reported. This novel ganoderma‐like heterostructure can not only efficiently disperse and confine the few‐layer MoS₂ nanosheets to fully expose the edge sites of MoS₂, and provide more opportunity to capture the Pt atoms, but also tune the electronic structure to modify the catalytic activity. Because of the favorable dispersibility and exposed large specific surface area, single Pt atoms can be easily anchored on MoS₂ nanosheets with ultrahigh loading of 1.8 at% (the highest is 1.3 at% to date). Owing to the ganoderma‐like structure and platinum atoms doping, this catalyst shows Pt‐like catalytic activity for the hydrogen evolution reaction with an ultralow overpotential of 34 mV and excellent durability of only 2% increase in overpotential for 72 h under the constant current density of 10 mA cm⁻².     

Density functional theory study of alloy element interstitials in Al

Density Functional Theory calculations were used to study Mg, Si, Cr, Mn, Fe, Co, Ni, and Cu interstitial configurations in Al. Energies of these elements in (100) dumbbell and octahedral configurations were determined. Results show that it is energetically favourable for metal alloying element atoms to replace Al selfinterstitials if the alloying atoms are smaller than the Al atoms, as expected. The system energy can thus be decreased by up to 2 eV. The difference between the energies of (100) dumbbell and octahedral configurations is only a few tenth eV for the alloys with metallic alloying elements. For Si, the difference can be up to 0.9 eV. This exceptional behavior of Si is most likely due to its angularly dependent bonding characteristics. Short ab-initio Molecular Dynamics simulations were performed on Mg and Si interstitials to allow these systems to evolve into different interstitial configurations rather than just the (100) dumbbell and octahedral configurations. For Si an alternative configuration with tetrahedral-like coordination was found. Consequences of the calculation results for radiation-induced segregation are discussed.     

Ni3Al合金硼原子占位及晶界偏聚

依据ＬＩ２型金属间化合物八面体，四面体间隙的特点，并利用硬球模型计算了上述各类间隙的空球半径大小，发现Ｎｉ３Ａｌ合金中６Ｎｉ八面体间空球半径比其他间隙大，使硼原子在更易进入６Ｎｉ八间隙，由于富Ｎｉ－Ｎｉ３Ａｌ合金晶界比Ａｌ－Ｎｉ３Ａｌ合金有更我的６Ｎｉ八面体间隙，所以硼在富Ｎｉ－Ｎｉ３Ａｌ晶界偏聚较多，另外富Ａｌ－Ｎｉ３Ａｌ合金晶界原子间作用力比富Ｎｉ－Ｎｉ３Ａｌ合金晶界原子间作用力大，这也阻碍了     

Ni doped Fe3O4 magnetic nanoparticles

In this work, the effect of nickel doping on the structural and magnetic properties of Fe3O4 nanoparticles is analysed. Ni(x)Fe(3-x)O4 nanoparticles (x = 0, 0.04, 0.06 and 0.11) were obtained by chemical co-precipitation method, starting from a mixture of FeCl2 x 4H2O and Ni(AcO)2 x 4H2O salts. The analysis of the structure and composition of the synthesized nanoparticles confirms their nanometer size (main sizes around 10 nm) and the inclusion of the Ni atoms in the characteristic spinel structure of the magnetite Fe3O4 phase. In order to characterize in detail the structure of the samples, X-ray absorption (XANES) measurements were performed on the Ni and Fe K-edges. The results indicate the oxidation of the Ni atoms to the 2+ state and the location of the Ni2+ cations in the Fe2+ octahedral sites. With respect to the magnetic properties, the samples display the characteristic superparamagnetic behaviour, with anhysteretic magnetic response at room temperature. The estimated magnetic moment confirms the partial substitution of the Fe2+ cations by Ni2+ atoms in the octahedral sites of the spinel structure.     

Influence of the nanoscale support on carbon deposition and carbon elimination over Ni/gamma-Al2O3 catalyst for CH4 conversion

Characteristics of carbon deposition by CH4 and carbon elimination by CO2 over conventional and nanoscale Ni/gamma-Al2O3 catalysts were investigated by using a pulse reaction, as well as by TGA, TEM, TPO-MS, H2-TPR and H2-chemisorption techniques. It was found that the behaviors of carbon deposition by CH4 decomposition and carbon elimination by CO2 depend on the active metal dispersion and the metal-support interaction. The filamentous carbon was formed on the conventional Ni/gamma-Al2O3 catalyst with low metal dispersion and relatively large particles, this type of filamentous carbon was far from the active centers and difficult to eliminate by CO2. On the other hand, the carbon deposition originated from CH4 decomposition on the nanoscale Ni/gamma-Al2O3 catalyst would mainly cover the surface of active centers, this type of highly active carbon was easily eliminated by CO2 because it is close to the active center Ni atoms. As a result, the improvement of coking-resistance was ascribed to the high metal dispersion and strong metal-support interaction, a model of CH4 decomposition carbon deposition on Ni/gamma-Al2O3 catalyst was proposed.     

Shape and composition-controlled platinum alloy nanocrystals using carbon monoxide as reducing agent

The shape of metal alloy nanocrystals plays an important role in catalytic performances. Many methods developed so far in controlling the morphologies of nanocrystals are however limited by the synthesis that is often material and shape specific. Here we show using a gas reducing agent in liquid solution (GRAILS) method, different Pt alloy (Pt-M, M = Co, Fe, Ni, Pd) nanocrystals with cubic and octahedral morphologies can be prepared under the same kind of reducing reaction condition. A broad range of compositions can also be obtained for these Pt alloy nanocrystals. Thus, this GRAILS method is a general approach to the preparation of uniform shape and composition-controlled Pt alloy nanocrystals. The area-specific oxygen reduction reaction (ORR) activities of Pt(3)Ni catalysts at 0.9 V are 0.85 mA/cm(2)(Pt) for the nanocubes, and 1.26 mA/cm(2)(Pt) for the nanooctahedra. The ORR mass activity of the octahedral Pt(3)Ni catalyst reaches 0.44 A/mg(Pt).