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Copper oxide was deposited on tubular TiO2 via Cu2+ introduction into a titanate nanotube aggregate followed by calcination. The titanate has a layered structure allowing Cu intercalation and can readily transform into anatase TiO2 via calcination for condensation of the constituting layers. The activity of the tubular catalysts, with a Cu content of 2 wt %, in selective NO reduction with NH3 was compared with those of other 2 wt % Cu/TiO2 catalysts using TiO2 nanoparticles as the support. The Cu species supported on the nanotubes showed a higher activity than those supported on the nanoparticles. X-ray absorption near-edge structure (XANES) analysis showed that the Cu species on all the TiO2 supports are in the +2 state. Extended X-ray absorption fine structure (EXAFS) investigations of these catalysts reflected higher degrees of CuO dispersion and Cu2+ dissolution into the TiO2 lattice for the tubular Cu/TiO2 catalysts. Absence of CuO bulk detection by a temperature-programmed reduction analysis for the tubular catalysts confirmed the high CuO-dispersion feature of the tubular catalysts. The dissolution of Cu2+ to form a CuxTi1-xO2 type of solid solution was improved by using an in-situ ion-intercalation method for Cu deposition on the nanotubes. A fraction as high as 40% for Cu2+ dissolution was obtained for the tubular catalysts while only 20% was obtained for the particulate catalysts. The CuxTi1-xO2 species were considered one form of the active sites on the Cu/TiO2 catalysts. 相似文献
3.
Joaquim C. G. Esteves da Silva Ade´lio A. S. C. Machado Marta S. S. D. S. Pinto 《Analytical and bioanalytical chemistry》1997,357(7):950-957
The complexation of Cu(II) by two samples of fulvic acids (FA) extracted from the raw sewage sludge (RsFA) of a waste water
processing plant and from the composted sludge (CsFA) obtained upon aerobical digestion was studied at pH 6.0. Synchronous
molecular fluorescence spectroscopy was used to monitor the association of FA with Cu(II) and a self-modelling mixture analysis
method (SIMPLISMA) was used to preprocess the spectral data to calculate the number of components with different quenching
profiles as function of the Cu(II) concentration and their spectra. The stability constants and a rough estimation of the
binding site concentrations were obtained by a Stern-Volmer analysis, by a non-linear least-square method and by a linear
procedure. The analysis of the SyF spectra allowed the identification of two binding sites for both samples. The logarithm
of the conditional stability constant corresponding to the 1:1 complex formed between the stronger binding site and Cu(II)
is about 4 for both samples.
Received: 22 April 1996 / Revised: 5 August 1996 / Accepted: 7 August 1996 相似文献
4.
Peter M. Rafailov Peter K. Sveshtarov Vladimir B. Mehandzhiev Ivalina Avramova Penka Terziyska Minko Petrov Boyko Katranchev Haritun Naradikian Stefan I. Boyadjiev Csaba Cserhti Zoltn Erdlyi Imre M. Szilgyi 《Molecules (Basel, Switzerland)》2022,27(6)
Graphene films were grown by chemical vapor deposition on Cu foil. The obtained samples were characterized by Raman spectroscopy, ellipsometry, X-ray photoelectron spectroscopy and electron back-scatter diffraction. We discuss the time-dependent changes in the samples, estimate the thickness of emerging Cu2O beneath the graphene and check the orientation-dependent affinity to oxidation of distinct Cu grains, which also governs the manner in which the initial strong Cu-graphene coupling and strain in the graphene lattice is released. Effects of electropolishing on the quality and the Raman response of the grown graphene layers are studied by microtexture polarization analysis. The obtained data are compared with the Raman signal of graphene after transfer on glass substrate revealing the complex interaction of graphene with the Cu substrate. 相似文献
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Mixed Cu,Mn, Cu,Mn,Al, Cu,Mg,Mn, and Cu,Mg,Mn,Al oxides were obtained by calcination of amorphous basic carbonate (Cu,Mn oxides) or hydrotalcite-like precursors at 300–800 °C. The product composition was characterized by chemical analysis, XRD, and voltammetry of the microparticles. The XRD amorphous portion was detected indirectly by XRD and directly by voltammetry. Tenorite (CuO) and spinels were the main crystalline components of the oxide mixtures. The presence of Al shifted the onset of the crystallization of XRD-detectable tenorite and spinel to temperatures higher by 100–200 °C, and the presence of Mg shifted tenorite crystallization by 100 °C, but voltammetry was able to detect these phases even in XRD-amorphous or nanocrystalline calcines. Voltammetry is hence suitable for analysis of poorly crystalline oxides that can be used in heterogeneous catalysis. 相似文献
7.
超声辐照下化学沉积法制备Cu/Al2O3复合粉体材料 总被引:4,自引:0,他引:4
声化学是利用超声波的空化效应产生局部高温高压等极端物理条件加速化学反应或改变化学反应途径的一门新学科.Cu/Al2O3复合粉末材料是一种近年来倍受关注的新型金属/非金属复合粉末材料.本文报道了超声在化学沉积法制备Cu/Al2O3复合粉末材料中的应用,... 相似文献
8.
Preparation and characterization of ultrafine Fe-Cu-based catalysts for CO hydrogenation 总被引:1,自引:0,他引:1
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The ultrafine particles of a new style Fe-Cu-based catalysts for CO hydrogenation were prepared by impregnating the organic sol of Fe(OH)3 and Cu(OH)2 onto the activated Al2O3, in which the organic sol of Fe(OH)3 and Cu(OH)2 were prepared in the microemulsion of dodecylbenzenesulfonic acid sodium(S)/n-butanol(A)/toluene(O)/water with V(A)/V(O) = 0.25 and W(A)/W(S) = 1.50. This catalyst was characterized by particle size analysis, XRD and TG. The results of particle size analysis showed that Fe(OH)3 particles with a mean size of 17.1 nm and Cu(OH)2 particles with an average size of 6.65 um were obtained. TG analysis and XRD patterns suggested that 673 K is the optimal calcination temperature. CO hydrogenation produced C+OH with a high selectivity above 58 wt% by using the ultrafine particles as catalyst, and the total alcohol yield of 0.250 g·ml^-1 ·h^-1 was obtained when the contents of Al2O3 and K were 88.61 wt% and 1.60 wt%, respectively. 相似文献
9.
Copper is an essential trace metal that shows a vertical recycled-scavenged profile in the ocean. To help elucidate the biogeochemical cycling of Cu in the present and past oceans, it is important to determine the distribution of Cu isotopes in seawater. However, precise isotopic analysis of Cu has been impaired by the low concentrations of Cu as well as co-existing elements that interfere with measurements by multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS). The objective of this study is to develop a simple Cu pre-concentration method using Nobias-chelate PA1 resin (Hitachi High Technologies). This extraction followed by anion exchange, allows precise analysis of the Cu isotopic composition in seawater. Using this method, Cu was quantitatively concentrated from seawater and >99.9999% of the alkali and alkaline earth metals were removed. The technique has a low procedural blank of 0.70 ng for Cu for a 2 L sample and the precision of the Cu isotopic analysis was ±0.07‰ (±2SD, n = 6). We applied this method to seawater reference materials (i.e., CASS-5 and NASS-6) and seawater samples obtained from the northwestern Pacific Ocean. The range of dissolved δ65Cu was 0.40–0.68‰. 相似文献
10.
Multivariate curve resolution, alternating least-squares is applied to spectra data obtained in the study of Cu(II) complexation by l-histidine. The combination of several chemometric techniques based on factor analysis (FA), singular value decomposition (SVD), evolving factor analysis (EFA), and multivariate curve resolution with constrained alternating least-squares (ALS) is used to determine the number of species and their distribution diagram. This multivariate analysis data treatment simultaneously reveals the species Cu, CuL, CuLH, CuL2, CuL2H, and CuLOH, through the calculated concentration profiles and allows the assignment of numerically obtained pure individual spectra. Formation constants of these species were calculated by hard-modeling methods applied potentiometric and spectrophotometric measurements. 相似文献
11.
Salar Amoli H Porgam A Bashiri Sadr Z Mohanazadeh F 《Journal of chromatography. A》2006,1118(1):82-84
In this study a rapid, simultaneous analysis of V, Ni, Fe and Cu in crude oil was achieved by high performance liquid chromatography using 10 cm length reversed-phase C18 column. Since the amount of metal ions is at a very low level, in this work, solvent extraction of metals by a ligand such as 8-hydroxyquinoline from acidic media was investigated with some modification to previous procedures. Average extraction recoveries were 99, 85, 94 and 96 for V, Ni, Fe and Cu, respectively. The proposed method was successfully applied to the crude oil which was obtained from Koshk area in southern Iran. Fast analysis of metal ion in reversed-phase short column was achieved with methanol/water (55/45, v/v) and the detection limits measured as three times the background noise were obtained. Also it was shown that if small amount of 8-hydroxyquinoline was added to the mobile phase, the peak height and the peak symmetry were improved. A typical chromatogram for the separation of the 8-hydroxyquinoline complexes of V (V), Ni (II), Fe (III) and Cu (II) in crude oil was obtained in less than 4 min. 相似文献
12.
Determination of trace impurities in zinc selenide was carried out by substoichiometric neutron activation analysis. Trace
impurities were separated from matrix elements by suitable procedures and determined by substoichiometric methods, i.e., Au
was extracted with rhodamine-B, Ag and Cu with dithizone, Cr with sodium diethyldithiocarbamate, Co with 1-nitroso-2-naphthol,
and Sb with cupferron. Two sorts of zinc selenide single crystals were supplied for analysis and the following values were
obtained as impurity concentration; Au 0.36, 0.076 ppb, Ag 42, 32 ppb, Cr. 1.8, 0.63 ppm, Co 0.16, 0.0079 ppm, Sb 8.5, 5.9
ppb and Cu 1.4, 0.44 ppm. The behavior of copper by heat-treatment of zinc selenide was also studied by means of substoichiometric
isotope dilution analysis. 相似文献
13.
Rahman Bikas Fatemeh Ajormal Nader Noshiranzadeh Marzieh Emami Anna Kozakiewicz 《应用有机金属化学》2020,34(10):e5826
A new 1D azido bridged Cu(II) coordination polymer with 1,3-oxazolidine based ligand, [Cu(H3L)(μ1,3-N3)(N3)]n ( 1 ), was synthesized and characterized by elemental analysis and spectroscopic methods. The structure of 1 was also determined by single crystal X-ray analysis which indicated the 1D polymeric chain is generated by end-to-end (EE) azide bridge. The obtained compound was employed as catalyst in green click synthesis of β-hydroxy-1,2,3-triazoles from one-pot three-component cycloaddition reaction of epoxide-azide-alkyne. The catalytic reactions were carried out in water as a safe, cheap and green solvent. The catalytic studies indicated that the obtained 1D azido bridged Cu(II) coordination polymer is an active catalyst for preparing β-hydroxy-1,2,3-triazoles. The effect of temperature on the selectivity of the catalytic system was studied and the results indicated this catalytic system has high selectivity at low temperatures. The structure the product obtained from the reaction of 2,3-epoxypropylphenylether, azide and 1-ethynyl-1-cyclohexanol ( T4 ) was determined by single crystal X-ray analysis. The results indicate Cu(II) coordination polymers can be a new class of catalytic systems for green click synthesis of 1,2,3-triazoles. 相似文献
14.
J. Maul A. S. Brito A. L. M. de Oliveira S. J. G. Lima M. A. M. A. Maurera D. Keyson A. G. Souza I. M. G. Santos 《Journal of Thermal Analysis and Calorimetry》2011,106(2):519-523
Copper monoxide (CuO) was successfully obtained by microwave-assisted hydrothermal method, using different conditions—in a
solution without base, in a solution alkalinized with NaOH or with NH4OH. The powders were analyzed by thermal analysis (TG/DTA), X-ray diffraction (XRD), infrared spectroscopy, UV–Visible spectroscopy,
and scanning electronic microscopy. XRD results showed that CuO was obtained with monoclinic structure and without secondary
phases. Thermal analysis and infrared spectra indicated the presence of acetate groups on the powder surface. TG curves also
showed a mass gain assigned to the Cu(I) oxidation indicating that a reduction possibly occurred during synthesis. The high
and broad absorption band in the UV–Vis spectroscopy from 250 to 750 nm indicated the coexistence of Cu(II) and Cu(I), confirming
the Cu(II) reduction, inside the CuO lattice. It was also possible to confirm the Cu(II) reduction by a displacement of the
Me–O vibration bands observed in the IR spectra at around 500 cm−1. 相似文献
15.
A direct inductively coupled plasma atomic emission method for the determination of Ag, Al, As, Ca, Cd, Co, Cu, Fe, Ga, K, Li, Mg, Na and Pb in high-purity tantalum powders has been developed. The electrothermal vaporization technique using a modified longitudinally-heated Grün-ETAAS furnace with sample introduction on a platform and an automated sampling workstation provided the possibility of in situ analyte-matrix separation, freedom of blank, and applicability to routine analysis. Hard- and software were modified to allow signal recording and data processing independent of the spectrometer software. The extent of spectral interferences by Ta-emission at the analyte wavelengths used was determined and the analyte signals of each sample run were automatically corrected. Limits of detection ranging from 5 ng/g (Ag, Cu) to 250 ng/g (K, Pb) were obtained using optimized furnace and spectrometer conditions. The method was applied to the analysis of two tantalum samples and the results for Cu, Fe, K, Mg and Na were compared with those obtained by liquid and solid-samping ETAAS, showing satisfactory agreement. 相似文献
16.
With glucose as reducing agent, Cu2O particles with different size and morphology were synthesized selectively by a seed-mediated growth approach. The major advantage of this process is that Cu(II) cannot be reduced to Cu metal. The size of the Cu2O particles can be controlled by changing the Cu(II) concentration in colloid solution. Square-shaped Cu2O particles (20-700 nm in diameter) were obtained in the presence of PEG 400, and polygonal-shaped Cu2O particles (approximately 1000 nm) were observed upon using triblock copolymer as modifier, while sphere-shaped Cu2O particles with a diameter of 400-700 nm were obtained in the absence of a modifier. 相似文献
17.
Cu-Ce-O mixed oxides from Ce-containing layered double hydroxide precursors: Controllable preparation and catalytic performance 总被引:1,自引:0,他引:1
Zheng Chang Na Zhao Feng Li David G. Evans Claude Forano 《Journal of solid state chemistry》2011,184(12):3232-3239
Cu/Zn/Al layered double hydroxide (LDH) precursors have been synthesized using an anion exchange method with anionic Ce complexes containing the dipicolinate (pyridine-2,6-dicarboxylate) ligand. Cu-Ce-O mixed oxides were obtained by calcination of the Ce-containing LDHs. The materials were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, thermogravimetry-differential thermal analysis, elemental analysis, and low temperature N2 adsorption/desorption measurements. The results reveal that the inclusion of Ce has a significant effect on the specific surface area, pore structure, and chemical state of Cu in the resulting Cu-Ce-O mixed metal oxides. The resulting changes in composition and structure, particularly the interactions between Cu and Ce centers, significantly enhance the activity of the Ce-containing materials as catalysts for the oxidation of phenol by hydrogen peroxide. 相似文献
18.
A. Elhassan A. Giakoumaki D. Anglos G.M. Ingo L. Robbiola M.A. Harith 《Spectrochimica Acta Part B: Atomic Spectroscopy》2008
In the present work we are studying the influence of pulse duration (nanosecond (ns) and femtosecond (fs)) at λ = 248 nm on the laser-induced plasma parameters and the quantitative analysis results for elements such as Sn, Zn and Pb, in different types of bronze alloys adopting LIBS in ambient atmosphere. Binary (Sn–Cu), ternary (Sn–Zn–Cu or Sn–Pb–Cu) and quaternary (Sn–Zn–Pb–Cu) reference alloys characterized by a chemical composition and metallurgical features similar to those used in Roman times, were employed in the study. Calibration curves, featuring linear regression coefficients over 98%, were obtained for tin, lead and zinc, the minor elements in the bronze alloys (using the internal standardization method) as well as for copper, the major element. The effects of laser pulse duration and energy on laser-induced plasma parameters, namely the excitation temperature and the electron density have been studied in our effort to optimize the analysis. Finally, LIBS analysis was carried on three real metal objects and the spectra obtained have been used to estimate the type and elemental composition of the alloys based on the calibration curves produced with the reference alloys. The results obtained are very useful in the future use of portable LIBS systems for in situ qualitative and quantitative elemental analysis of bronze artifacts in museums and archaeological sites. 相似文献
19.
Ghattas W Giorgi M Mekmouche Y Tanaka T Rockenbauer A Réglier M Hitomi Y Simaan AJ 《Inorganic chemistry》2008,47(11):4627-4638
Several Cu(II) complexes with ACC (=1-aminocyclopropane carboxylic acid) or AIB (=aminoisobutyric acid) were prepared using 2,2'-bipyridine, 1,10-phenanthroline, and 2-picolylamine ligands: [Cu(2,2'-bipyridine)(ACC)(H2O)](ClO4) (1a), [Cu(1,10-phenanthroline)(ACC)](ClO4) (2a), [Cu(2-picolylamine)(ACC)](ClO4) (3a), and [Cu(2,2'-bipyridine)(AIB)(H2O)](ClO4) (1b). All of the complexes were characterized by X-ray diffraction analysis. The Cu(II)-ACC complexes are able to convert the bound ACC moiety into ethylene in the presence of hydrogen peroxide, in an "ACC-oxidase-like" activity. A few equivalents of base are necessary to deprotonate H2O2 for optimum activity. The presence of dioxygen lowers the yield of ACC conversion into ethylene by the copper(II) complexes. During the course of the reaction of Cu(II)-ACC complexes with H2O2, brown species (EPR silent and lambda max approximately 435 nm) were detected and characterized as being the Cu(I)-ACC complexes that are obtained upon reduction of the corresponding Cu(II) complexes by the deprotonated form of hydrogen peroxide. The geometry of the Cu(I) species was optimized by DFT calculations that reveal a change from square-planar to tetrahedral geometry upon reduction of the copper ion, in accordance with the observed nonreversibility of the redox process. In situ prepared Cu(I)-ACC complexes were also reacted with hydrogen peroxide, and a high level of ethylene formation was obtained. We propose Cu(I)-OOH as a possible active species for the conversion of ACC into ethylene, the structure of which was examined by DFT calculation. 相似文献
20.
A novel one-step chemical method for preparation of copper nanofluids 总被引:11,自引:0,他引:11
This paper presents a novel one-step method for preparing of copper nanofluids by reducing CuSO(4).5H(2)O with NaH(2)PO(2).H(2)O in ethylene glycol under microwave irradiation. Nonagglomerated and stably suspended Cu nanofluids are obtained. The influences of CuSO(4) concentration, addition of NaH(2)PO(2), and microwave irradiation on the reaction rate and the properties of Cu nanofluids were investigated by transmission electron microscopy, infrared analysis, and sedimentation measurements. It is found to be a fast, efficient one-step chemical method to prepare Cu nanofluids. 相似文献