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1.
Stable geometries, electronic structures, and magnetic properties of the ZnO monolayer doped with 3d transition‐metal (TM) (Sc, Ti, V, Cr, Mn, Fe, Co, Ni, and Cu) atoms substituting the cation Zn have been investigated using first‐principles pseudopotential plane wave method within density functional theory (DFT). It is found that these nine atomic species can be effectively doped in the ZnO monolayer with formation energies ranging from ?6.319 to ?0.132 eV. Furthermore, electronic structures and magnetic properties of ZnO monolayer can be modified by such doping. The results show that the doping of Cr, Mn, Fe, Co, Ni, and Cu atoms can induce magnetization, while no magnetism is observed when Sc, Ti, and V atoms are doped into the ZnO monolayer. The magnetic moment is mainly due to the strong p–d mixing of O and TM (Cr, Mn, Fe, Co, Ni, and Cu) orbitals. These results are potentially useful for spintronic applications and the development of magnetic nanostructures. © 2013 Wiley Periodicals, Inc.  相似文献   

2.
电镀Fe-Cr-Ni合金显微结构研究①李东林*刘建平郭芳洲华建荣(南方冶金学院化工系,江西赣州341000)Fe-Cr-Ni合金,一直是电镀工作者研究的对象[1,2].A.M.Anderson[3]等人从多种Cr(Ⅲ)的水溶液中镀出了Fe-Cr-Ni...  相似文献   

3.
Method of sorption–atomic-absorption determination of Co, Cr, Cu, Fe, Mn, and Ni in samples of high-purity Nb2O5 with heterochain S,N-containing sorbents was developed. The method is based on the sorption preconcentration of trace impurities followed by their determination by high-resolution continuum source graphite furnace atomic absorption spectrometry (HR CS GFAAS). Selectivity of three original inhouse synthesized S,N-containing heterochain sorbents was studied. The recoveries of Co, Cr, Cu, Fe, Mn, and Ni using heterochain sorbents OKS, MTH, and GLSH were 100, 80, and 76%, correspondingly. Sorbent “OKS”, which provided the quantitative recovery of trace impurities, was chosen for further research. The sorption conditions for chloride solutions of different acidities (0.1–3 M HCl) were studied and optimized. Using the conditions established for the sorption and HR CS GFAAS analysis, trace Co, Cr, Cu, Fe, Mn, and Ni were determined in high purity Nb2O5 with a relative error less than 5%. The trueness control of the obtained results is confirmed by the “added–found” method. The developed method allows us to determine concentrations of analytes: 0.02–0.20 ppm Co, 2.0–3.3 ppm Cr, 0.2–1.5 ppm Cu, 6.0–21.0 ppm Fe, 0.6–0.8 ppm Mn, and 2.8–3.5 ppm Ni. The proposed methodology can be successfully extended to the determination of various trace elements in other high-purity inorganic materials.  相似文献   

4.
采用磁悬浮感应熔炼方法制备了V2.1TiNi0.4Zr0.06Cu0.03M0.10(M=Cr, Co, Fe, Nb, Ta)储氢电极合金, 通过X射线衍射(XRD)、扫描电子显微镜(SEM)、电子衍射能谱(EDS)分析和电化学测试等手段系统研究了添加元素M对合金微结构与电化学性能的影响. 结果表明, 所有合金均由BCC结构的V基固溶体主相和C14型Laves第二相组成, 且第二相沿主相晶界形成三维网状分布; Cr、Nb 和Ta元素主要分布在合金主相中, 而Co和Fe元素主要分布在第二相中. 电化学性能测试表明, 在V2.1TiNi0.4Zr0.06Cu0.03合金中掺加Cr、Co、Fe、Nb或Ta元素后, 虽然会降低最大放电容量, 但能有效抑制合金中V和Ti的腐蚀溶出, 提高电极充放电循环稳定性; 同时还能明显改善合金的高倍率放电性能. 相比之下, V2.1TiNi0.4Zr0.06Cu0.03Cr0.10合金具有最佳的综合电化学性能.  相似文献   

5.
Neutron activation analysis methods for the determination of impurities in zirconium cladding material and uranium oxide are described. Detection limits for the elements Al, Cd, Cr, Co, Cu, Hf, Fe, Mn, Ni, W and U in zirconium are below that required by the ASTM B 352-79 standard. The method has been tested on the NIST SRM 360a Zircaloy-2 from which the elements Na, Mg, Al, Ca, V, Cr, Fe, Co, Ni, Cu, Eu and U have been detected. The values for Cr, Fe, Ni and Cu are compared with the certified values. A method for the pre-irradiation separation of the elements Mg, Na, Al, K, Sc, Ca, V, Mn, Cr, Fe, Co, Cu, Zn, Rb, Zr, Cd, Cs, REE and Hf from uranium has been developed. A neutron activation analysis method for the determination of those elements in uranium is described. The method is tested by the analysis of the IAEA reference sample SR-54/64. The elements Al, Mn, V, Cu, Cr, Co, Ni and Fe have been detected and the results compared with the certified values.  相似文献   

6.
The catalytic oxygen electroreduction properties of PtTiMe (Me = Co, Cr, Cu, Fe, Mn, Mo, Ni, Pd, Ta, V, W and Zr) ternary alloys were studied using an in-house developed thin film based combinatorial high throughput method. Libraries containing discrete alloy compositions were fabricated by plasma co-sputtering and the resulting alloys were electrochemically screened by the hydrodynamic rotating disk electrode technique. Candidate catalysts were identified by comparing the activity-stability-composition relationships between the platinum titanium alloys and pure platinum standard. Among the PtTiMe alloys studied, PtTiNi, PtTiCu and PtTiV, respectively, displayed the highest catalytic oxygen electroreduction activities with a tenfold, an eightfold and a sixfold enhancement as compared to the pure platinum standard and good chemical stabilities.  相似文献   

7.
过渡金属离子置换钛酸纳米管的制备和光催化活性   总被引:4,自引:0,他引:4  
TiO2纳米粉体和纳米膜材料在光催化降解大气和水中的污染物等方面具有广泛的应用[1]。近年来,以TiO2为原料与浓N aO H反应合成的钛酸纳米管具有比其原料TiO2更大的表面积和孔体积,且对丙烯有光催化氧化降解活性而备受关注[2]。以往在对TiO2纳米粉体和纳米膜材料在光催化研究中,人们发现由于光激发产生的电子与空穴的复合,导致光量子效率很低。为克服这个缺点,人们使用过渡金属离子掺杂等多种手段对TiO2进行改性[3]。但钛酸纳米管相类似的研究还未见报道。对钛酸纳米管的结构和组成的研究表明[4],此纳米管状物的组成是N axH2-xTi3O7,…  相似文献   

8.
A series of complexes of stoichiometry [MX2(dipyS)] {dipyS = bis(2–picolyl)-1,3–dithiopropane); M=Cr, Mn, Fe, Co, Ni, X=Cl; M=Ni or Cu, X=NO3} and [VOCl(dipyS)]Cl have been prepared and characterised, including the X-ray crystal structure of [Ni(ONO2)2(dipyS)]. The kinetics of the transfer of dipyS from these complexes (M=Cr, Mn, Fe, Co or Ni) to Cu2+, to form [Cu(dipyS)]2+, have been studied in MeOH. For M=Ni, the kinetics are consistent with a mechanism involving rate-limiting dissociation of the initial pyridyl—M bond. Subsequent binding of Cu2+ to the pendant pyridyl-residue (or binding Cl– to the vacant site on M) is followed by the complete transfer of dipyS from M to Cu. For M=Cr, Mn or Co, the same mechanism is believed to operate, but in these cases intermediates in the dipyS transfer to Cu2+ have been detected spectroscopically. Evidence is presented that these intermediates have Cu2+ bound to a pendant pyridyl-group on [MCl2(dipyS)] and that the subsequent complete transfer of dipyS involves rate-limiting dissociation of a M—S bond. For M=Fe, e.p.r. spectroscopy shows that the complex is a dimer in solution. However, the transfer reaction with Cu2+ involves an analogous intermediate to that with M=Cr, Mn or Co, but only at high concentrations of Cu2+. Unexpectedly, the binding of Cu2+ inhibits the transfer of dipyS from Fe to Cu. The electronic factors which give rise to this behaviour are discussed.  相似文献   

9.
为开发和利用赣南野生草菇提供科学依据,采用原子吸收光谱法测定了其中Zn、Co、Ni、Cu、Fe、Cr和Mg7种金属元素的含量。结果表明,草菇中Zn、Co、Ni、Fe、Cr和Mg含量丰富,Cu含量较低,Zn与Cu值为7.4,与抗癌中药中微元素的含量有Zn高Cu低的关系相同,说明赣南野生草菇有较高的营养价值。  相似文献   

10.

The reverse depth profile analysis is a recently developed method for the study of a deposit composition profile in the near-substrate zone. The sample preparation technique enables one to separate the deposit and a thin cover layer from its substrate, and the initial roughness of the sample is much smaller than in the conventional sputtering direction. This technique is particularly suitable to study the zones being formed in the early phase of the electrodeposition of alloys. It has been demonstrated with the reverse depth profile analysis that in many cases when one component of an alloy is preferentially deposited, an initial zone is formed that is rich in the preferentially deposited component. This phenomenon is demonstrated for Ni–Cd, Ni–Sn, Fe–Co–Ni, Co–Ni, and Co–Ni–Cu alloys. The composition change is confined to the initial 150-nm-thick deposit, and it is the result of the interplay of the deposition preference and the depletion of the electrolyte near the cathode with respect to the ion reduced preferentially. The reverse depth profile analysis made it possible to compare the measured and the calculated composition depth profile of electrodeposited multilayers. It has been shown that the decay in the composition oscillation intensity in Co/Cu multilayers with the increase of the sputtering depth can be derived from the roughness measured as a function of the deposit thickness.

  相似文献   

11.
The reverse depth profile analysis is a recently developed method for the study of a deposit composition profile in the near-substrate zone. The sample preparation technique enables one to separate the deposit and a thin cover layer from its substrate, and the initial roughness of the sample is much smaller than in the conventional sputtering direction. This technique is particularly suitable to study the zones being formed in the early phase of the electrodeposition of alloys. It has been demonstrated with the reverse depth profile analysis that in many cases when one component of an alloy is preferentially deposited, an initial zone is formed that is rich in the preferentially deposited component. This phenomenon is demonstrated for Ni–Cd, Ni–Sn, Fe–Co–Ni, Co–Ni, and Co–Ni–Cu alloys. The composition change is confined to the initial 150-nm-thick deposit, and it is the result of the interplay of the deposition preference and the depletion of the electrolyte near the cathode with respect to the ion reduced preferentially. The reverse depth profile analysis made it possible to compare the measured and the calculated composition depth profile of electrodeposited multilayers. It has been shown that the decay in the composition oscillation intensity in Co/Cu multilayers with the increase of the sputtering depth can be derived from the roughness measured as a function of the deposit thickness.  相似文献   

12.
Procedures based on flameless atomic absorption spectrometry are described for the determination of Cd, Co, Cr, Cu, Ni and Pb in mineral waters. Because of matrix effects and the inadequate detection limits for direct determinations, the metals are separated from the macrocomponents by precipitation of their tetramethylenedithiocarbamates with iron(III) as collector, or by co-precipitation on Fe(OH)3. The detection limits are 0.005, 0.3, 0.08. 0.10, 2 and 0.10 μg l- for Cd, Co, Cr, Cu, Ni and Pb, respectively, and are satisfactory for the determination of these elements in mineral waters. The precision is 2–7%.  相似文献   

13.
运用浸渍法制备了七种过渡金属氧化物催化剂.对于NH3 分解反应均可获得很高的NH3转化率;对于NH3分解Claus反应则可以获得较高的SO2转化率和单质硫选择性.通过比较发现Co3O4-TiO2和Fe2O3-TiO2催化剂的低温活性比较高.经过XRD表征发现,在NH3分解Claus反应中,催化剂的活性相可能是过渡金属硫化物.结合活性评价和XRD表征结果提出了NH3分解Claus反应的机理.  相似文献   

14.
过渡金属氧化物[1,2]及负载型贵金属催化剂[3~13]是催化氧化消除CO的有效催化剂,一直是研究的热点. 虽然对MOx和Au/MOx上CO的氧化性能研究得较多,但大多是在无水条件下进行的;涉及催化剂抗水性能的报道较少[3,9,10],且仅限于对催化剂活性的研究. Haruta等[3]对Au/Fe2O3,Au/Co3O4和Au/TiO 2等体系开展了一些工作, 认为水对CO氧化活性有促进作用. 本文重点考察了水对MOx(M=Al,Ca,Co,Cr,Cu,Fe,La,Mn,Ni和Zn)催化剂上CO氧化活性的影响,以及水对Au/MOx 催化剂活性及稳定性的影响.  相似文献   

15.
The rate of the gas-phase oxidation of ethanol, 2-propanol, acetone, ethyl acetate, dioxane, and benzene with atmospheric oxygen is studied on surfaces of bimetallic oxide catalysts Co–Fe, Cu–Fe, Cr–Co, and Ni–Fe, prepared via thermal decomposition of double complex compounds in air. It is found that the rate of oxidation of volatile compounds depends on the volume of the transient pores in the catalyst sample. The rate of oxidation on the same catalyst at 350°C depends on the nature of the substance in the order: acetone > ethyl acetate > ethanol > propanol > dioxane, benzene.  相似文献   

16.
Summary The analysis of ashes being of increasing importance, a reference material was prepared from fly ash of a city waste incinerator. The procedures of preparation, homogeneity and stability testing are described as well as the way of certification of elements of major importance: Cd, Co, Cr, Cu, Fe, Hg, Ni, Pb, Zn, Sb, Se and Tl.
Zertifizierung der Gehalte an Cd, Co, Cu, Fe, Hg, Ni, Pb, Zn, Sb, Se, Tl und Cr in einer Stadtmüll-Verbrennungsasche
Zusammenfassung Da die Analyse von Aschen zunehmend an Bedeutung gewinnt, wurde von der Flugasche einer Stadtmüll-Verbrennungsanlage ein Referenzmaterial hergestellt. Die Methoden der Herstellung sowie der Homogenitätsund Stabilitätsprüfung werden beschrieben und die Art der Zertifizierung der Elemente von hauptsächlicher Bedeutung aufgezeigt (Cd, Co, Cr, Cu, Fe, Hg, Ni, Pb, Zn, Sb, Se, Tl).
  相似文献   

17.
新型Schiff碱单核及异双核配合物的合成及光谱特征   总被引:10,自引:1,他引:9  
首次报道了新型Schiff碱配合物--双[N,N'-亚乙基-2,2'-(苯亚甲基)二(3,4-二甲基吡咯-5-醛缩亚胺)]合单金属配合物MH2L[M=Mn(Ⅱ),Fe(Ⅲ)Cl,Cr(Ⅲ)Cl,Cu(Ⅱ),Co(Ⅱ),Ni(Ⅱ),Zn(Ⅱ)]及异双金属配合物MnML[M=Fe(Ⅲ)Cl,Cr(Ⅲ)Cl,Cu(Ⅱ),Co(Ⅱ),Ni(Ⅱ),Zn(Ⅱ)]的合成方法及光谱特征.  相似文献   

18.
Summary A method for the flame photometric determination of Fe, Ni, Co, Cu, Mn, Al, and Cr in various waters is described. Samples can be analysed directly after removal of interfering anions or after separation (and concentration) of the elements to be determined from any interfering cations. Fe, Ni, Co, and Cu are extracted as carbamates, Al as cupferronate, and Cr as the ion-association complex HCrO3Cl. The extractant used for all is hexone.The elimination of the interference of Mg with Fe is discussed. The variation of the relative error of the emission measurement with the concentration of the elements was investigated.
Zusammenfassung Eine Methode zur flammenphotometrischen Bestimmung von Fe, Ni, Co, Cu, Mn, Al und Cr in Wässern wurde beschrieben. Nach Entfernung der störenden Anionen oder nach Abtrennung (und Anreicherung) der zu bestimmenden Elemente von etwa störenden Kationen können die Proben direkt analysiert werden. Fe, Ni, Co und Cu werden als Carbamate extrahiert, Al als Cupferronat und Cr in Form des Ionen-Assotiationskomplexes HCrO3Cl. Als Extraktionsmittel dient in allen Fällen Hexon.Die Beseitigung des störenden Einflusses von Magnesium bei der Eisenbestimmung wurde diskutiert. Die Variation des relativen Fehlers der Emissionsmessung mit der Konzentration der Elemente wurde untersucht.

Résumé On décrit une méthode pour le dosage par photométrie de flamme du Fe, Ni, Co, Cu, Mn, Al et Cr dans des eaux variées. On peut faire l'analyse directe après élimination des anions qui interfèrent ou après séparation (et concentration) des éléments à doser d'avec les cations gênants. On extrait Fe, Ni, Co et Cu sous forme de carbamates, Al en cupferronate, et Cr à l'état de complexe par association ionique, HCrO3Cl. Dans tous les cas, on utilise l'hexone comme agent d'extraction.On discute l'élimination de l'interférence du Mg par le Fe. On a suivi la variation de l'erreur relative dans la mesure de l'émission en fonction de la concentration des éléments.


Paper presented at the Symposium on Analytical Chemistry, Graz, 29th September–1st October 1965.  相似文献   

19.
The molecular parameters have been calculated to confirm the geometry of 3-methyl-5-oxo-N,1-diphenyl-4,5-dihydro-1-H-pyrazole-4-carbothioamide, HL. The compound is introduced as a new chelating agent for complexation with Cr(III), Fe(III), Co(II), Ni(II) and Cu(II) ions. The isolated chelates were characterized by partial elemental analyses, magnetic moments, spectra (IR, UV–vis, ESR; 1H NMR) and thermal studies. The protonation constant of HL (5.04) and the stepwise stability constants of its Co(II), Cu(II), Cr(III) and Fe(III) complexes were calculated. The ligand coordinates as a monobasic bidentate through hydroxo and thiol groups in all complexes except Cr(III) which acts as a monobasic monodentate through the enolized carbonyl oxygen. Cr(III) and Fe(III) complexes measured normal magnetic moments; Cu(II) and Co(II) measured subnormal while Ni(II) complex is diamagnetic. The data confirm a high spin and low spin octahedral structures for the Fe(III) and Co(II) complexes. The ESR spectrum of the Cu(II) complex support the binuclear structure. The molecular parameters have also been calculated for the Cu(II) and Fe(III) complexes. The thermal decomposition stages of the complexes confirm the MS to be the residual part. Also, the thermodynamic and kinetic parameters were calculated for some decomposition steps.  相似文献   

20.
本文利用定性价键理论、半经验分子轨道法和分子轨道碎片法,讨论了通式为M_3S_4L_9M′X~(n+)(M=Cr,Mo,W;M′=Fe,Co,Ni,Cu;n=0,4,5)的异核过渡金属簇合物Cr_3S_4Cp_3FeOOCCMe_3(1),Cr_3S_4Cp_3CoCO(2),Mo_3S_4(NH_3)_9FeOH_2~(4+)(3)和Mo_3S_4(OH_2)_9NiOH_2~(4+)(4)的电子结构,成键性质,以及活性元件(碎片)L_9M_3S_4~(n+)和M′X组装的合理性。指出了由于碎片组装成类立方烷后,电子从M′原子转移到M原子,使得过渡金属原子M的氧化态低于不完整类立方烷中的M原子。此外,本文还根据价键理论和分子轨道法的集居数分析,给出簇合物骨架的相对稳定性顺序是Mo_3S_4FC~(4+)>Cr_3S_4Fe~(4+)>Cr_3S_4Co~(4+)>Mo_3S_4Ni~(4+)。  相似文献   

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