Design of the Metal Precursors Molecular Structures in Impregnating Solutions for Preparation of Efficient Ni Mo/Al_2O_3 Hydrodesulfurization Catalysts

The molecular structures of metal precursors in the impregnating solution were designed so as to prepare efficient Ni Mo/Al_2O_3 hydrodesulfurization(HDS) catalysts. At first, five typical impregnating solutions were designed; the existing metal precursors, such as [Mo4(citrate)2O11]^(4-)-like, [P2Mo18O62]^(6-)-like and [P2Mo5O23]^(6-)-like species in the solutions were confirmed by laser Raman spectroscopy(LRS). The UV-Vis spectra results indicated that the solutions containing both phosphoric acid and citric acid could change the existing form of nickel species. Five corresponding Ni Mo/Al_2O_3 catalysts were prepared by the incipient wetness impregnation method. The LRS analysis results of dried catalysts showed that the above metal precursors could be partly retained on alumina support after impregnation and drying, although the interface reaction between different metal precursors and alumina support unavoidably took place. Then the catalysts were sulfided and characterized by N2 physisorption, TEM and XPS analyses. The results showed that different metal precursors in impregnating solution could mainly result in the difference in both the morphology of(Ni)Mo S2 slabs and the promoting effect of Ni species. The catalyst prepared mainly with [P2Mo5O23]^(6-)-like species used as precursors exhibited worse dispersion of(Ni)Mo S2 slabs and lower ratio of Ni–Mo–S active phases than the one with [Mo4(citrate)2O11]^(4-)-like species. Promisingly, the catalyst prepared with co-existing [Mo4(citrate)2O11]^(4-)-like, [P2Mo18O62]^(6-)-like and [P2Mo5O23]^(6-)-like species showed better hydrodesulfurization activity for 4,6-DMDBT thanks to its more well-dispersed Ni–Mo–S active phases.

Effect of thermal pretreatment of metal precursor on the properties of Cu_2ZnSnS_4 films

Zn/Sn/Cu （CZT） stacks were prepared by RF magnetron sputtering. The stacks were pretreated at different tem- peratures （200℃, 300 ℃, 350 ℃, and 400 ℃） for 0.5 h and then followed by sulfurization at 500℃ for 2 h. Then, the structures, morphologies, and optical properties of the as-obtained Cu2ZnSnS4 （CZTS） films were studied by x-ray diffraction （XRD）, Raman spectroscopy, UV-Vis-NIR, scanning electron microscope （SEM）, and energy-dispersive x-ray spectroscopy （EDX）. The XRD and Raman spectroscopy results indicated that the sample pretreated at 350℃ had no secondary phase and good crystallization. At the same time, SEM confirmed that it had large and dense grains. According to the UV-Vis-NIR spectrum, the sample had an absorption coefficient larger than 10^4 cm-1 in the visible light range and a band gap close to 1.5 eV.

Application of CO_2-TPD in the Synthesis of Composite Oxides from Metal-Organic Precursors

CO2-TPD was demonstrated an effective way to investigate the phase formation during pyrolysis for the preparation of composite oxides using metal-organic molecules as precursors.Based on the CO2-TPD results, it was found that calcination condition had deep effect on the carbonate formation and the minimum firing temperature to acquire pure phase composite oxide.An optimized calcination schedule was then developed.

Formation of Ultrafine Metal Particles and Metal Oxide Precursor on Anodized Al by Electrolysis Deposition

Nickel was deposited by ac electrolysis deposition in the pores of the porous oxide film of Al produced by anodizing in phosphoric acid. Ultrafine rod-shaped Ni particles were formed in the pores. At the same time a film of Ni oxide precursor was developed on the surface of the porous oxide film. The Ni particles and the Ni oxide precursor were examined by SEM, TEM and X-ray diffraction. The thickness of the barrier layer of the porous oxide film was thin and it attributed to the formation of the metal particles, while the formation of the oxide precursor was associated with the surface pits which were developed in the pretreatment of Al.

Formation of Copper Nickel Bimetallic Nanoalloy Film Using Precursor Inks

Precursor (Metal-organic decomposition (MOD)) inks are used to fabricate 2D and 3D printed conductive structures directly onto a substrate. By formulating a nanoalloy structure containing multiple metals, the opportunity to modify chemical and physical properties exists. In this paper, a copper-nickel bimetallic nanoalloy film was fabricated by mixing copper and nickel precursor inks and sintering them in vacuum. The individual elemental inks were formulated and characterized using SEM, EDS, and XRD. During thermal processing, elemental copper forms first and is followed by the formation of bimetallic copper-nickel alloy. The encapsulation of the underlying copper by the nickel-rich alloy provides excellent oxidation resistance. No change in film resistance was observed after the film was exposed to an oxygen plasma. Nanoalloy films printed using reactive metallic inks have a variety of important applications involving local control of alloy composition. Examples include facile formation of layered nanostructures, and electrical conductivity with oxidative stability.

STUDY ON THE INTERACTION BETWEEN POLYVINYLPYRROLIDONE AND PLATINUM METALS DURING THE FORMATION OF THE COLLOIDAL METAL NANOPARTICLES

Several PVP-stabilized colloidal platinum metals nanoparticles have been synthesized and characterized by FTIR and TEM.Comparing with the pure PVP,carbonyl groups of PVP in the mixture of PVP and the metal precursors or in the PVP-stabilized metal nanoparticles have obvious peak shifts in FTIR spectra.The peak shifts reveal the interaction between PVP and the metal species.The interaction between PVP and metal precursors has effect on the formation of the colloidal metal nanoparticles.Strength of the intera...

借助平衡吸附法研究不同添加剂对钼物种在氧化铝表面吸附行为的影响

为了探究金属浸渍液中各物种在氧化铝载体表面的竞争吸附,通过在溶液中引入不同类型的添加剂进行了相应的平衡吸附试验。结果发现在七钼酸铵溶液中引入偏钨酸铵会在一定程度上降低钼平衡吸附量,二者在氧化铝中性羟基上的竞争吸附有利于减弱钨物种与氧化铝的强相互作用。在七钼酸铵溶液中分别引入硝酸铵、氯化铵、硫酸铵、丙三醇和聚乙二醇对钼平衡吸附量影响不大,但引入磷酸或其铵盐则可明显降低钼平衡吸附量,表明其可与钼物种产生较强的竞争吸附,从而减弱钼物种与氧化铝的相互作用,促进钼物种的硫化。引入柠檬酸铵也可明显降低钼平衡吸附量。另外,氧化铝载体在以[PMo_(12)O_(4)0]^(3-)结构为主的磷钼酸溶液中的钼平衡吸附量明显高于在以[P_(2)Mo_(5)O_(23)]^(6-)结构为主的磷钼酸溶液中的钼平衡吸附量。而且,通过调控含有柠檬酸的镍钼浸渍液中P/Mo物质的量之比,可以改变钼前驱体的分子结构以及游离的磷酸根和柠檬酸根离子的数量;并且氧化铝的钼平衡吸附量随着溶液中P/Mo物质的量之比的提高而逐渐降低。研究结果为统筹设计金属浸渍液的组成以及开发高效加氢催化剂提供了必要的理论和技术支持。

多孔氮化硼材料的制备及其吸附性能研究

以二甲胺、三氯化硼、氨气和甲胺为原料,通过多步反应得到氮化硼前驱体三(甲胺基)环硼氮烷,经高温烧结后得到多孔氮化硼材料。通过FTIR、NMR对氮化硼前驱体中间体二氯(二甲胺基)硼烷和三(二甲胺基)环硼氮烷以及前驱体三(甲胺基)环硼氮烷的结构进行表征。利用XRD和SEM对多孔氮化硼结构和形貌进行表征。结果表明:通过反应合成前驱体中间物,最终能够合成出含碳量较低的氮化硼前驱体三(甲胺基)环硼氮烷。研究了多孔氮化硼材料对重金属离子的吸附能力,确定了多孔氮化硼材料对各种金属离子的吸附能力。研究发现:利用前驱体中间物制备出的多孔氮化硼具有较高的比表面积,吸附性能优异,能够有效的去除掉溶液中的重金属离子。使用有机前驱体法制备氮化硼弥补了无机制备中元素分布不均,易吸潮,易粉化的缺点。

磷酸铁工业废水处理工艺研究进展

近年来锂离子电池正极材料磷酸铁锂广受关注,带动其前驱体磷酸铁相关研究及生产呈现爆发式增长。然而,主流工艺生产磷酸铁的过程中会产生大量废水,制约了磷酸铁行业绿色、健康发展。目前,已报道的磷酸铁工业废水处理方法有沉淀法、硫酸铵镁结晶法、微生物分解法、膜分离法等,但是沉淀法污泥难处理、难回收,磷酸铵镁法需额外加入药剂以满足沉淀配比,微生物法稳定性及灵活性较差,膜分离法需配合其他处理技术对膜进水预处理并对膜浓水处理回用,因此工业化应用中常将多种技术结合,形成综合处理方法,可对磷酸铁废水达到较好的处理效果。最后,从废水高效预处理及有价元素回收再利用方面入手,对未来磷酸铁行业的废水处理技术进行了展望。

微波消解原丝和碳纤维的前处理方法

测定碳纤维和其前驱体原丝中微量金属元素的含量对碳纤维生产企业掌握碳纤维和原丝的性能至关重要。作为一种兴起的样品前处理方法,微波消解法具有操作步骤简单、耗时短、准确性高的特点,可以应用到碳纤维和原丝的消解领域。本文使用微波消解方法对PAN原丝及碳纤维样品进行前处理,并制备了可供ICP测试的待测样品。实验结果表明,在碳纤维和原丝微量金属元素含量的检测过程中,可以采用微波消解法代替传统的灰化法进行样品的前处理,并得到检测结果准确和重现性较好的消解试样。

Plasma-enhanced atomic layer deposition of Co using Co(MeCp)_2 precursor

Cobalt （Co） thermal or plasma enhanced atomic layer deposition （PE-ALD） was investigated using a novel metal organic precursor, Co（MeCp）2, and NH3 or H2 or their plasma as a reactant. The growth characteristics, electrical and microstructural properties were investigated. Especially, PE-ALD produced Co thin films at low growth temperature down to 100℃. Interestingly, the low temperature growth of Co films showed the formation of columnar structure at substrate temperature below 300℃. The growth characteristics and films properties of PE-ALD Co using bis（η-methylcyclopentadienyl） Co（II） （Co（MeCp）2） was compared with those of PE-ALD Co using other Cp based metal organic precursors, bis-cyclopentadienyl cobalt （II） （CoCp2） and cyclopentadienyl isopropyl acetamidinato-cobalt （Co（CpAMD））.

A Novel Method to Fabricate Steel-Al Foam Sandwich Panel with Metallic Bonding

Al foam sandwich panel(AFS) with metallic bonding was fabricated by foaming a hotpressed three-layer composite with two steel facesheets and a melt route precursor as core. The melt route precursor was fabricated by dispersing undecomposed blowing agent into molten Al, followed by solidification. Microstructures of the joints during fabrication process were analyzed by scanning electron microscopy(SEM) and energy dispersive spectroscopy(EDS). Static three-point bending was conducted to evaluate joint quality of the AFS. It was found that a primary bonding was achieved by hot-pressing and significant diffusion layer of Fe-Al intermetallic compounds was sustained between steel and Al foam core by foaming. Damage modes of the AFS under three-point bending were dominated by indentation, plastic hinges, core shear and crack. Delamination between steel and foam was absent, implying that reliable metallic bonding was achieved. This method allows for producing large-scale AFS with steel facesheets.

MOCVD of Molybdenum Sulphide Thin Film Via Single Solid Source Precursor Bis-(Morpholinodithioato-s,s’)-Mo

A single solid source precursor bis-(morpholinodithioato-s,s’)-Mo was prepared and molybdenum sulphide thin film was deposited on sodalime glass using Metal Organic Chemical Vapour Deposition (MOCVD) technique at deposition temperature of 420?C. The film was characterized using Rutherford Backscattering Spectroscopy (RBS), Ultraviolet-Visible Spectroscopy, Four point probe technique, Scanning Electron Mi-croscopy (SEM), X-ray Diffractometry (XRD) and Atomic Force Microscopy (AFM). A direct optical band gap of 1.77 eV was obtained from the analysis of the absorption spectrum. The sheet resistance was found to be of the order of 10P–5P ΩP–1P?cmP–1P. SEM micrographs of the films showed the layered structure of the film with an estimated grain size that is less than 2 μm while XRD indicates parallel orientation of the basal plane to the substrate surface.

Highly Dispersed Pd Nanoparticles Supported on Zr-Doped MgAl Mixed Metal Oxides for 2-Ethylanthraquinone Hydrogenation

In this study,Pd-Mg(Al)-LDH/γ-Al2O3 and Pd-Mg(Al)Zr-LDH/γ-Al2O3 precursors were synthesized by impregnating Na2PdCl4 on Mg(Al)-LDH/γ-Al2O3 and Mg(Al)Zr-LDH/γ-Al2O3,and then the precursors were calcinated and reduced to obtain Pd-Mg(Al)-MMO/γ-Al2O3 and Pd-Mg(Al)Zr-MMO/γ-Al2O3 catalysts.Compared with Pd/γ-Al2O3 catalyst,the hydrogenation efficiency of Pd-Mg(Al)-MMO/γ-Al2O3 and Pd-Mg(Al)Zr-MMO/γ-Al2O3 increased by 15.7%and 24.0%,respectively.Moreover,the stability of Pd-Mg(Al)Zr-MMO/γ-Al2O3 catalyst was also higher than that of Pd/γ-Al2O3.After four runs,the hydrogenation efficiency of Pd/γ-Al2O3 decreased from 12.1 to 10.0 g/L,while that of Pd-Mg(Al)Zr-MMO/γ-Al2O3 decreased from 15.0 to 14.3 g/L.The active aquinones selectivities of all catalysts were almost 99%.The structures of the catalysts were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),N2 adsorption–desorption,inductively coupled plasma-atomic emission spectrometry(ICP-AES),CO chemisorption analysis,transmission electron microscopy(TEM),temperature-programmed reduction with hydrogen(H2-TPR),and X-ray photoelectron spectroscopy(XPS).The results indicate that the improved catalytic performance is attributed to the stronger interaction between Pd and Mg(Al)Zr-MMO/γ-Al2O3,smaller Pd particle size and higher Pd dispersion.This work develops an effective method to synthesize highly dispersed Pd nanoparticles based on the layered double hydroxides(LDHs)precursor.

Impact of preparation conditions on hydrogen storage performance of metallic Ti-doped NaAlH_4

Contrary to the popular opinion, it has been found that metallic Ti powder can be directly utilized as dopant precursor to prepare catalytically enhanced NaAlH4 through mechanical milling. As a novel method for preparation of catalytically enhanced NaAlH4, direct metallic Ti-doping possesses practical advantage over the state-of-the-art doping technology: elimination of the inactive by-products and the gas impurities that are highly detrimental to fuel cell operation. A systematic investigation along this new approach was performed under various preparation conditions, including different starting materials, milling atmosphere and milling time. The materials thus prepared under different conditions were found to share some common features, while at the meantime, differ significantly from each other on hydrogen storage performance. A comprehensive understanding of these results provides valuable insight into a series of fundamental questions in catalytically enhanced Ti-NaAlH4 system.

Preparation of Nano-Sized γ-Al_2O_3 Supported Iron Catalyst for Fischer-Tropsch Synthesis by Solvated Metal Atom Impregnation Methods

Two types of small iron clusters supported on γ-Al2O3-RT（dehydroxylated at room temperature） and γ-Al2O3-800 （dehydroxylated at 800 ℃） were prepared by solvated metal atom impregnation （SMAI） techniques. The iron atom precursor complex, bis（toluene）iron（0） formed in the metal atom reactor, was impregnated into γ-Al2O3 having different concentrations of surface hydroxyl groups to study the effect of surface hydroxylation on the crucial stage of iron cluster formation. Catalysts prepared in this way were characterized by TEM, Mǒssbauer, and chemisorption measurements, and the results show that higher concentration of surface hydroxyl groups of γ-Al2O3-RT favors the formation of more positively charged supported iron cluster Fen/γ-Al2O3-RT, and the lower concentration of surface hydroxyl groups of γ-Al2O3-800 favors the formation of basically neutral supported iron cluster Fen/γ-Al2O3-800. The measured results also indicate that the higher concentration of surface hydroxyl groups causes the rapid decomposition of precursor complex, bis（toluene）iron（0）, and favors the formation of relatively large iron cluster. Consequently, these two types of catalysts show different catalytic properties in Fischer-Tropsch reaction. The catalytic pattern of Fen/γ-Al2O3-RT in F-T reaction is similar to that of the unreduced γ-Fe2O3 and that of Fen/γ-Al2O3-800 is similar to that of the reduced α-Fe2O3.

Preparation of Highly Dispersed Supported Metal Catalysts via Solvated Metal Atom Impregnation ( V) --The Effects of Hydroxyl Group on the Surface Concentrations of SiO2 on the Properties of Supported Fe Clusters

Two kinds of small iron clusters supported on SiO2-200 (dehydroxylated at 200℃ and SiO2-600 (de-hydroxylated at 600℃) were prepared by Solvated Metal Atom Impregnation (SMAI) techniques. The iron atom precursor complex, bis (toluene) iron(0) formed in the metal atom reactor, was impregnated into SiO2 having different concentrations of surface hydroxyl groups to study the effect of surface hydroxylation on the crucial stage of iron cluster formation. Catalysts prepared in this way were characterized by THM, Mosbauer and chemisorption measurements, and the resules show that higher concentration of surface hydroxyl groups of SiO2-200 favours the formation of more positively charged support iron cluster Fen/SiO2-200 and the lower concentration of surface hydroxyl groups of SiO2-600 favours the formation of basically neutral supported iron cluster Fe2/SiO2-600. The measured results also indicate that the higher concentration of surface hydroxyl groups causes the precursor complex,bis(toluene) fron(0), to decompose more rapidly, and favours the formation of relatively large iron cluster. As a consequence, these two kinds of catalysts show different catalytic properties in Fischer-Tropsch reaction. The catalytic pattern of Fe/SiO2-200 in F-T reaction is similar to that of the unreduced a-Fe2O2, while Fe2/SiO2 -600 is similar to that of reduced α-Fe2O2.

The Reaction Of Metal Trialkyls With Benzo[H]Quinolin-10-ol

The reaction of the trialkyl metals (R3M, R = Me, Et; M = Ga, In) with benzo[h]quinolin-10-ol (HO-BQ) in a 1:1 molar ratio gave intramolecular N coordinated complexes R2M-O-BQ (M = Ga, R = Me 1, Et 2) and (R2In-O-BQ)(2) (M = In, R = Et 3,) in 80-90% yield. The molecular structures of complexes 1 and 3 have been established by X-ray crystallography.

Metal Organic Chemical Vapour Deposited Thin Films of Cobalt Oxide Prepared via Cobalt Acetylacetonate

The single solid source precursor, cobalt （Ⅱ） acetylacetonate was prepared and characterized by infrared spectroscopy. Thin films of cobalt oxide were deposited on soda lime glass substrates through the pyrolysis （metal organic chemical vapour deposition （MOCVD）） of single solid source precursor, cobalt acetylacetonate, Co[C5H7O2]2 at a temperature of 420℃. The compositional characterization carried out by rutherford backscattering spectroscopy and X-ray diffraction （XRD）, showed that the films have a stoichiometry of Co2O3 and an average thickness of 227±0.2 nm. A direct energy gap of 2,15±0.01 eV was calculated by the data obtained by optical absorption spectroscopy. The morphology of the films obtained by scanning electron microscopy, showed that the grains were continuous and uniformly distributed at various magnifications, while the average grain size was less than i micron for the deposited thin films of cobalt oxide.