Solutions Of Nickel Salts Research Articles

Effects of pH and chelating agent on the NiWS phase formation in NiW/γ-Al2O3 HDS catalysts

In this article, NiW/γ-Al2O3 samples were prepared by consecutive impregnations of a W/γ-Al2O3-based catalyst with aqueous solution of nickel salt. The structural control of the nickel ion precursor in the impregnation solution was achieved by the addition of 1,2-cyclohexanediamine-N,N,N′,N′-tetraacetic acid (CyDTA) as a chelating agent. The influence of pH of this aqueous solution on the NiWS phase formation in the sulfided catalysts was investigated. Coordination structures of the Ni–CyDTA complexes were evaluated by FT-IR and DRS UV–Vis spectroscopies. Sulfided catalysts were characterized by X-ray photoelectron spectroscopy (XPS) and high resolution transmission electron microscopy (HRTEM) and tested in hydrodesulfurization (HDS) of 4,6-dimethyldibenzothiophene (4,6-DMDBT) carried out in a batch reactor at 593 K and total H2 pressure of 55 bar. Spectroscopic characterization by DRS UV–Vis showed the predominance of the [Ni(CyDTA)]2− species in solution. Following the impregnation and drying steps, the [Ni(CyDTA)]2− complex showed no apparent changes of its structure, independent of the pH value of impregnation solution. The Ni/W/γ-Al2O3 catalysts ex [Ni(CyDTA)]2− complex exhibited high stability. The presence of CyDTA delayed the reduction of Ni and caused a remarkable decrease of the W-support interaction, thus increasing the formation of NiWS phase upon catalyst sulfiding. The catalyst activity–structure correlation demonstrated that the catalyst activity and selectivity is linked with formation of the most active NiWS phase having single or double WS2 slab structures. The catalyst prepared with [Ni(CyDTA)]2− complex at pH of 4.0 exhibited the largest initial HDS activity, which was approximately triple compared with the CyDTA-free counterpart. For all catalysts, the HDS reaction proceeded via hydrogenation (HYD) and direct desulfurization (DDS) reaction routes, the former being the main reaction route. The addition of chelating agent led to an increase of the selectivity toward HYD route products.

Modification of Fe Alloys by Magnetic Field

Electrodeposition is a very promising alternative to the physical vapor deposition techniques (PVD) to produce soft magnetic layers and microstructures. The advantage of electrodeposition in comparison to PVD processes is the fact that it is an inexpensive method.Moreover, it allows depositing high aspect ratio layers with a thickness ranging from a few monolayers up tomore than 1 mm onto a complex geometry substrate.The deposited layer properties could be tailored by a proper selection of the process parameters. A superposition of an external magnetic field during the electrodeposition has gained a considerable attention during the past decade, since it can affect the deposit properties. Mainly the morphology of the deposited layers is infuenced. The electrodeposition process of Fe-Ni films was examined in a presence of homogenous magnetic field(B: up to 0,6 T). Sulphate nickel and sulphate iron salt solution was used with pH 4,3.The changes of surface morphology of Fe films electrodeposited without a magnetic field is observed.The magnetic field superimposing perpendicular to the electric field leads to the hydrogen evolution promotion by MHD convection. This enhances the hydrogen evolution and the changes in Fe ions mass transfer appear near electrode surface. A change of local pH at the electrode is present and formation of different morphology of Fe layer.

P-Type dye-sensitized solar cell based on nickel oxide photocathode with or without Li doping

Abstract Nickel oxide (NiO) nanostructures are synthesized using a microwave-assisted hydrothermal method. The hydrothermal bath has a solution of nickel salt mixed with precipitating agent. During the synthesis the microwave temperature, the concentration of nickel salt and precipitating agent along with the pH of the reaction solutions are changed and different morphologies of nickel oxide are obtained. The resulting nickel oxide nanostructures are characterized using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, Brunauer–Emmett–Teller method and X-ray photoelectron spectroscopy. Thus formed NiO has been used as a photocathode in dye-sensitized solar cell. Lithium doped NiO showed better IPCE as well as solar to electrical conversion efficiency than the undoped NiO.

Effect of the calcination temperature on Ni/MgAl2O4 catalyst structure and catalytic properties for partial oxidation of methane

Effect of calcination temperature on Ni/MgAl2O4 catalyst was investigated in order to evaluate changes on structural and catalytic properties for catalytic partial oxidation of methane. The catalysts were calcined at different temperatures after impregnation of nickel salt solution on MgAl2O4 support. The prepared catalysts showed nearly 89% CH4 conversion and 99% H2 selectivity under the flow of 157,000 (lkg−1h−1) with the ratio of CH4/air=0.44 at 1atm and 800°C. However, turnover frequency values of the catalysts were between 8.2 and 42.3s−1 and increased according to Ni particle size. Lewis basicity/acidity ratio increased from 2.14 to 4.46 with increasing calcination temperature. It was found that coking rate on the catalysts depends on Ni particle size and surface basicity/acidity. The experimental results showed that calcination temperature and time have a significant influence on both structural and catalytic properties of the catalysts that show strong metal oxide support interaction. It could be claimed that high calcination temperatures could be beneficial to obtain highly active, selective and stable Ni/MgAl2O4 catalysts, which possess strong metal oxide support interaction, by maintaining Ni dispersion high after reduction, increasing surface basicity and enhancing the stability of Ni particles against sintering.

Pulse-Current Electrodeposition for Loading Active Material on Nickel Electrodes for Rechargeable Batteries

Although the pulse-current electrodeposition method is a commonly used technique, it has not been widely employed in electrode preparation. This method was applied to sintered nickel electrodes in a nickel salt solution containing additives. The active material that was obtained, nickel hydroxide, was studied using different characterization techniques. Electrodes impregnated with pulse current had higher capacity than those impregnated with continuous current. The active material is homogeneous and compact with optimum loading and good performance during discharge. These characteristics would provide a large amount of energy in a short time due to an increase in the electrode kinetic reaction.

Effect of chemical composition on the photocatalytic activity of potassium polytitanates intercalated with nickel ions

Results of a synthesis and study of the photocatalytic properties of nanosize powder compounds based on amorphous potassium polytitanate, modifi ed with nickel ions are reported. The effect of protonation is noted, resulting in an increase in the specifi c surface area and adsorption capacity of the substances obtained. It is shown that the increase in the photoactivity of potassium polytitanates modifi ed in aqueous solutions of nickel salts is due to the formation of multiple potassium polytitanate-NiOx semiconductor heterojunctions on the surface and to the doping of potassium polytitanate with nickel ions.

Preparation of Iron Nanoparticles and Steel Plant Wastewater Treatment

The iron nanoparticles were prepared via a redox reaction between Fe2+ and BH4- in the SDS-ethanol-water system.The iron nanoparticles surface was treated by nickel salt solution. The particles were characterized by the Transmission Electronic Microscope(TEM) and X-Ray Diffraction(XRD).It is shown that γ type iron nanoparticles with a mean size of 50nm have been prepared. The wastewater in the steel plant was treated by the iron nanoparticles. It is shown that suspended substance and concentration of heavy metal ion in wastewater were brought down largely.

Catalytic behavior of carbon supported Ni–B, Co–B and Co–Ni–B in hydrogen generation by hydrolysis of KBH 4

Activated carbon (AC) supported Ni–B, Co–B, and Co–Ni–B catalysts with different Co/Ni mass ratios were synthesized by impregnation of commercial activated carbon with the solution of cobalt and/or nickel salt, and then reduction of metal salts with sodium borohydride at room temperature. Structural properties and morphology of the catalysts were studied using inductively coupled plasma (ICP), XRD and SEM techniques. The B content of the catalyst is less than that required for stoichiometric alloy formation, which indicates the simultaneous presence of the Co and/or Ni metal along with Co–B and/or Ni–B alloy on the surface of activated carbon. The catalytic activity of the catalysts has been tested by measuring the hydrogen generation rate during the hydrolysis of potassium borohydride in basic medium. The results show that Co–B/AC exhibits the highest activity among Ni–B/AC, Co–B/AC and Co–Ni–B/AC catalysts investigated. For supported bimetallic boride catalysts, the catalytic activity increases with Co/Ni mass ratio. The effects of reaction parameters, such as KBH 4 concentration, NaOH concentration, and reaction temperature, on the reaction were also surveyed.

Thiosemicarbazones의 몇 가지 코팔트(II) 및 니켈(II) 착물에 대한 합성, 항박테리아 및 항균 활성

두 가지 새로운 thiosemicarbazone으로, 예를 들면, 4[N-(4'-ethylbenzalidene)amino]antipyrine thiosemicarbazone(EBAAPTS) 및 4[N-(2',4'-dimethylbenzalidene)amino]antipyrine thiosemicarbazone(DMBAAPTS)를 합성하여 그 특성을 규명하였다. 이들 thiosemicarbazone(EBAAPTS 및 DMBAAPTS)의 코발트(II) 및 니켈(II)에 대한 착물화 특성을 조사하였다. EBAAPTS 및 DMBAAPTS와 코발트(II) 및 니켈(II) 염과의 반응을 뜨거운 에탄올 용액에서 수행한 결과, 일반적 조성으로 [<TEX>$MX_2(L)H_2O$</TEX>] (M=<TEX>$Co^{2+}$</TEX> 또는 <TEX>$Ni^{2+}$</TEX>; X=<TEX>$Cl^-$</TEX>, <TEX>$Br^-$</TEX>, <TEX>$NO_3^-$</TEX>, <TEX>$NCS^-$</TEX> 또는 <TEX>$CH_3COO^-$</TEX>; L=EBAAPTS 또는 DMBAAPTS)을 갖는 새로운 착물의 형성을 확인하였다. 새롭게 합성한 이들 착물에 대해 원소분석, 분자량, 몰전도도, 자기수자율, 적외선 및 자외선 분광학 등의 방법으로 특성을 규명하였다. 니트로벤젠 용액에서 이들 착물의 몰전도도를 측정한 결과, 비전해질 성질을 가짐을 알았다. 또한, 모든 착물은 높은-스핀 형태였다. 분광학적 연구로부터 [<TEX>$MX_2(L)H_2O$</TEX>] 형의 코발트(II) 및 니켈(II) 착물은 팔면체의 기하구조를 갖는 것으로 확인되었다. 이들 착물을 이용하여 항박테리아 및 항균 활성을 여러 종류의 병원균, 세균 및 박테리아에 대해 조사하여 생물학적 활성을 고찰하였다. In the present paper two new thiosemicarbazones i.e., 4[N-(4'-ethylbenzalidene)amino]antipyrine thiosemicarbazone (EBAAPTS) and 4[N-(2',4'-dimethylbenzalidene)amino]antipyrine thiosemicarbazone (DMBAAPTS) have been synthesized and characterized. The complexing abilities of these thiosemicarbazones i.e. EBAAPTS and DMBAAPTS towards cobalt(II) and nickel(II) salts have been explored. The reactions of the hot ethanolic solutions of cobalt(II) and nickel(II) salts with EBAAPTS and DMBAAPTS led to the formation of the novel complexes of general composition [<TEX>$MX_2(L)H_2O$</TEX>] (M=<TEX>$Co^{2+}$</TEX> or <TEX>$Ni^{2+}$</TEX>; X=<TEX>$Cl^-$</TEX>, <TEX>$Br^-$</TEX>, <TEX>$NO_3^-$</TEX>, <TEX>$NCS^-$</TEX> or <TEX>$CH_3COO^-$</TEX>; L=EBAAPTS or DMBAAPTS). The newly synthesized complexes have been characterized by elemental analyses, molar mass, molar conductance, magnetic susceptibility, infrared and electronic spectral studies. The molar conductance measurements of the complexes in nitrobenzene correspond to their non-electrolytic nature. All the complexes are of high-spin type. On the basis of spectral studies an octahedral geometry has been assigned for Co(II) and Ni(II) complexes of the type [<TEX>$MX_2(L)H_2O$</TEX>]. These complexes were screened for their antibacterial and antifungal activities on different species of pathogens, fungi and bacteria and their biopotency has been discussed.

Synthesis and characterization of W-SBA-15 and W-HMS as supports for HDS

W-modified HMS and SBA-15 mesoporous materials (Si/W molar ratio equal to 40) were synthesized using sodium tungstate as tungsten source. In order to prepare NiW catalysts these mesoporous materials were impregnated with an aqueous solution of nickel salt of 12-tungstophosphoric acid Ni3/2PW12O40. The synthesized W-HMS, W-SBA-15 materials and NiW catalysts have been characterized by SBET, XRD, UV–Vis DRS, FT-IR, TPD of NH3, 29Si MAS NMR, SEM and HRTEM. The influence of these particular supports on catalytic activity of NiW catalysts was studied in the reaction of hydrodesulfurization (HDS) of thiophene. The results from the FT-IR and UV–Vis DR spectroscopy confirm incorporation of W into the HMS and SBA-15 structures. Additionally 29Si MAS NMR measurements revealed relatively stronger effect of W ion incorporation in HMS structure on degree of silica cross-linking as compared to the effect of W ion incorporation in SBA-15 structure. The catalytic study showed that both W-HMS and W-SBA-15 materials modified with W are good supports for NiW catalysts in the HDS reaction of thiophene. The catalysts show lower selectivity for butanes than a reference NiW/γ-Al2O3 catalyst leveling of about 10% for chosen experimental conditions.

Single point electrodeposition of nickel for the dissymmetric decoration of carbon tubes

Dissymmetric micro- and nanoobjects are of enormous interest in many areas ranging from molecular electronics to targeted drug delivery. So far it has been quite difficult to synthesize dissymmetric objects at these scales and most approaches are based on using interfaces to break the symmetry. Only a few bulk procedures are known so far to produce the so-called Janus-type objects. We report here a simple approach for the bulk generation of dissymmetric micro- and nanoobjects, especially carbon tubes (CTs), based on a known, but so far underestimated electrochemical principle, namely bipolar electrodeposition. A suspension of CTs is introduced in a capillary containing an aqueous nickel salt solution and a high electric field is applied to orientate and polarize the individual tubes. During their transport through the capillary under sufficient polarization, each tube is the site of water oxidation at one end, and of Ni 2+ reduction at the other one. The resulting nickel deposit at one end of the tube allows manipulation of the objects with the help of a magnetic field.

Metal induced crystallized poly-Si Thin Films and Thin Film Transistors

Metal induced crystallization of a-Si was implemented by using nickel salt solution, nickel silicon oxide mixture, and a nano-layer of SiO2 mask. By using salt solution to form nickel media, the crystallization of a-Si started from many isolated sites and proceeded along radial directions at the isotropical crystallization rate under the optimized soaking conditions. By using nickel silicon oxide mixture, the crystallization of a-Si behaved an effect of self-controlled release of nickel, the poly-Si had low nickel residua under the induce holes and at the domain boundaries. By using a nano-layer of SiO2 mask to pre-define nucleation lines, the poly-Si composing of continuous zonal domain in exactly same width was obtained, the crystallization of a-Si started from some isolated sites inside the inducing windows, then proceeded along radial/lateral direction outside the windows. The characteristics of poly-Si TFTs made with these three different schemes were analyzed.

Extensive NMRD studies of Ni(II) salt solutions in water and water–glycerol mixtures

Aqueous solutions of simple nickel(II) salts are a classical test case for theories of the paramagnetic relaxation enhancement (PRE) and its dependence on the magnetic field (nuclear magnetic relaxation dispersion, NMRD), going back to late fifties. We present here new experimental data, extending the NMRD range up to 21 T (900 MHz). In addition to salt solutions in (acidified) water, we have also measured on solutions containing glycerol. The aqueous solution data do not show any significant changes compared to the earlier experiments. The interpretation, based on the general (“slow-motion”) theory is also similar to the earlier work from our laboratory. The NMRD-data in mixed solvents are qualitatively different, indicating that the glycerol not only changes the solution viscosity, but may also enter the first coordination sphere of the metal ion, resulting in lower symmetry complexes, characterized by non-vanishing averaged zero-field splitting. This hypothesis is corroborated by molecular dynamics simulations. A strategy appropriate for interpreting the NMRD-data for the chemically complicated systems of this type is proposed.

Generation and Reactivity of Enantiomeric (BINOLato)Ni+ Complexes with Chiral Secondary Alcohols in the Gas Phase

In the presence of secondary alcohols, electrospray ionization of dilute methanolic solutions of nickel(II) salts and 1,1'-bis-2-naphthol (BINOL) leads to complexes of the formal composition [(BINOLato)Ni(CH3CH(OH)R)]+ (BINOLato refers to a singly deprotonated (R)- or (S)-1,1'-bis-2-naphthol ligand; R=CH3, C2H5, n-C3H7, n-C4H9, n-C5H11, n-C6H13, c-C6H11, and C6H5). Upon collision-induced dissociation, each mass-selected nickel complex either loses the entire secondary alcohol ligand or undergoes bond activation followed by elimination of the corresponding ketone, as revealed by deuterium labeling. When enantiomeric BINOLato ligands (R or S) are combined with chiral secondary alcohols (R or S), differences in the branching ratios between these channels for the two stereoisomers of the secondary alcohols provide insight into the chiral discrimination operative in the C--H- and O--H-bond activation processes. For saturated alkan-2-ols, the chiral discrimination is low, and if any preference is observed at all, ketone elimination from the homochiral complexes (R,R and S,S) is slightly favored. In contrast, the diastereomeric (BINOLato)Ni+ complexes of 1-phenylethanol exhibit preferential ketone losses for the heterochiral systems (S,R and R,S).

The Fabrication and Magnetic Properties of Ni Fibers Synthesized Under External Magnetic Fields

AbstractOne‐dimensional (1D) nanocrystallites Ni fibers with different lengths were fabricated by the reduction of Ni2+ ions by hydrazine hydrate in the presence of external magnetic fields. The effect of the reaction conditions and magnetic field intensity on the microstructures and magnetic properties of the Ni fibers were systematically investigated by scanning electron microscopy (SEM), X‐ray diffraction (XRD), and measurement of hysteresis loops at room temperature. It was found that both the intensity of the external magnetic field and the concentration of the nickel salt solution played key roles in governing the microstructures and magnetic properties of the Ni fibers. Namely, the mean length of the Ni fibers increased markedly with increasing Ni2+ ion concentration and intensity of the external magnetic field as well. Moreover, the Ni fiber samples prepared under external magnetic fields had higher squareness and coercivity values than those synthesized in the absence of the external magnetic field. Therefore, a relatively high intensity of the external magnetic field and concentration of the Ni2+ ions was selected for the preparation of the desired Ni fibers with improved microstructures and magnetic properties. The present approach has the advantages of having a fast reaction rate and low cost and might be promising for the effective control of the shape and magnetic properties of magnetic materials and for large‐scale production as well. The resulting Ni fibers might be potential catalysts, magnetic storage materials, and conductive fillers for shielding of electromagnetic interference (EMI). (© Wiley‐VCH Verlag GmbH &amp; Co. KGaA, 69451 Weinheim, Germany, 2008)

Correlation between electron state density change and the electrical resistivity and magnetic permeability changes in the nanostructured powder of the NiMo alloy

The nanostructured powders of the Ni 95.4Mo 4.6 and Ni 99Mo 1 alloys (average crystallite dimensions of 14 and 21 nm) were obtained by the electrochemical deposition from ammonium solutions of nickel and molybdenum salts. The method of differential scanning calorimetry (DSC) and measurement of temperature dependence of the powder's electrical resistivity, magnetic permeability and the thermoelectromotive force were employed to examine structural changes of the powders. The nanocrystalline alloys Ni 95.4Mo 4.6 and Ni 99Mo 1 were stable up to about 460 K. The thermal stabilization of the alloys takes place within the temperature interval of 460–570 K. As a result of this process, a decrease in the electrical resistivity and increases in magnetic permeability as well as electron state density in the proximity of the Fermi level are observed. The crystallization temperature depends upon the current density of powder formation. The nanocrystalline alloy Ni 95.4Mo 4.6 obtained at j=70 mA cm −2 becomes crystallized in the temperature range between 650 and 840 K, while the Ni 99Mo 1 alloy obtained at j=180 mA cm −2 crystallizes in the 580–950 K temperature interval. The electrical resistivity and magnetic permeability of the nanocrystalline alloy decreased while the alloy's electron state density near the Fermi level increased after the process of crystallization took place. The electrical resistivity decrease recorded during the structural changes was due to an increase in the electron state density in the proximity of the Fermi level, as well as to an increase in the mean free path of the conducting electrons.

Solution synthesis of the unsupported Ni–W sulfide hydrotreating catalysts

Three solution synthesis routes for the preparation of unsupported Ni–W–S hydrotreating catalysts were compared. In all of them WO 2S 2 2− core was applied as precursor, but the reaction between Ni and W species was done in different ways. The preparation methods included solution reaction between WO 2S 2 2− and nickel species in the presence of organic surfactant (liquid–liquid route), reaction of amorphous high surface area nickel compound with aqueous WO 2S 2 2− species (liquid–solid route) and reaction of amorphous WOS 2 solid with aqueous solution of nickel salt (solid–liquid route). The catalysts were characterized by several techniques including X-ray powder diffraction, specific surface area and pore volume measurements, transmission electron microscopy and X-ray photoelectron spectroscopy (XPS). The catalytic activities were evaluated in thiophene hydrodesulfurization (HDS), toluene hydrogenation (HYD) and pyridine hydrodenitrogenation (HDN) reactions. It has been shown that highly active unsupported sulfides can be obtained from three routes. The highest weight activity was observed for the most finely dispersed liquid–liquid preparation. However, the relation between catalytic activity and texture is not linear and the preparation having low surface area and containing NiS bulky particles covered by curved WS 2 slabs showed the highest activity per unit of surface area.

Synthesis of unsupported Ni–W–S hydrotreating catalysts from the oxothiosalt (NH4)2WO2S2

Abstract Synthetic routes for the preparation of unsupported Ni–W–S hydrotreating catalysts were studied. In the preparations studied, amorphous tungsten oxysulfide WO x S y was used obtained from the acid condensation or thermal decomposition of (NH 4 ) 2 WO 2 S 2 salt. Amorphous WO x S y solid was promoted by nickel salt solutions and eventually stabilized by addition of organic molecules. The products were characterized by X-ray powder diffraction, specific surface area and pore volume measurements. The catalytic activities of Ni–W–S systems were evaluated for the thiophene hydrodesulfurization (HDS) reaction. It has been shown that highly active unsupported tungsten sulfides can be obtained from thermal decomposition of (NH 4 ) 2 WO 2 S 2 but not from acid condensation. Addition of organics such as nonionic Triton 114 surfactant to the impregnating solution strongly improved the textural properties and HDS activity of the unsupported Ni–W–S catalysts.

Structural and textural characterisation of NiMo catalysts supported on various zeolites

Structural and textural characterisation of NiMo catalysts supported on various zeolites Structural and textural properties of nickel-molybdenum catalysts supported on four various type of zeolites of different chemical composition and porous structure have been studied by the methods of IR, XRD and the low-temperature sorption of nitrogen. The catalysts have been obtained by the two-stage impregnation of the supports with the solutions of nickel and molybdenum salts by the method of incipient wetness. The catalysts have been shown to preserve the structure characteristic of the appropriate zeolite supports.

Synthesis of hollow microspheres of nickel using spheres of metallic zinc as templates under mild conditions

In recent years, hollow spheres of nanometer to micrometer dimensions have attracted special interests because of their potential applications in many areas [1, 2]. For example, they can serve as extremely small container for encapsulation which may benefit the control of delivery and release process of drugs and protection of environment-sensitive materials such as enzymes [3]. When it comes to fillers in making composite materials, hollow spheres can also show some advantages over their counterparts for their relatively low densities [4]. Various approaches have been proposed for preparing hollow spheres. For example, hollow polymer, oxide and glass composite spheres in micrometer-size range can be synthesized by physical methods such as spray drying techniques [5, 6]. Chemical methods can also be used to fabricate hollow spheres and soft template synthesis is a general one [7, 8]. For example, Micrometer-sized hollow spheres of CdS have been also been synthesized through an in situ source-template interface reaction route [9]. However, so far there are few reports on the fabrication of metal hollow spheres by chemical methods [10, 11]. Fortunately, a template-engaged method has been introduced recently and presents good prospect for the synthesis of metal hollow spheres by simple chemical methods [12]. But in this approach, only noble metals were used as templates and no further experimental data were given to prove the possibility of applying this method to other metals. Here our experiment will give a strong support to the generality of this method and provide a cheap approach to fabricate hollow nickle spheres for future industrial application. In our experiment, we utilize the replacement reaction between nickel and zinc to form nickel shells on the surfaces of zinc spheres by reacting nickel salt solution with solid template of zinc under carefully controlled conditions. Hollow nickel micrometer spheres were obtained by removing the residual cores of zinc and zinc oxide via washing with NaOH aqueous solution. In a typical experiment, 0.50 g zinc powders were first dispersed into 5 ml acetone, which was then added into 100 ml distilled water. After strongly stirring for 10 min, the mixture of zinc and water were kept for 40 s to separate the few large zinc spheres from the main part of zinc spheres by gravity, and then the suspended part