共查询到20条相似文献,搜索用时 62 毫秒
1.
铜磷铝分子筛的合成及其对苯液相氧化制苯酚的催化性能 总被引:8,自引:0,他引:8
以水热法合成了铜磷铝分子筛(Cu-AlPO4-5),并用XRD,ICP,SEM,FT-IR,NH3-TPD,H2-TPR,ESR和N2吸附-脱附等手段对样品进行了表征. 结果表明,所合成的Cu-AlPO4-5分子筛具有AFI拓扑结构,结晶度高,无结晶态杂质; Cu2+进入到分子筛的骨架结构中,并使其Lewis酸和Brnsted酸中心数量增加,弱酸性中心大大增强,强酸性中心消失; 样品中的Cu存在多种形式,以骨架Cu物种为主,还存在 泄羌芡釩uO和双核Cu物种,部分样品具有缺陷结构. Cu-AlPO4-5分子筛中存在着骨架Cu和缺陷结构两种可能的活性中心,对苯液相氧化具有良好的催化性能,苯酚选择性可达96%,收率可达6.9%. 相似文献
2.
Steffen Strehle Rainer Reiche Volker Hoffmann Jörg Acker Thomas Gemming Klaus Wetzig 《Mikrochimica acta》2006,156(1-2):167-172
Cu(Ag) films are a promising interconnect material due to their low electrical resistivity and due to an expected increase
of the electromigration resistance by alloying effects compared to pure copper films. Besides the alloying element also impurities
are incorporated into the film during the electrochemical deposition process, which can retard or enhance electromigration
damage. An impurity element of special interest is sulfur, which could probably improve the interconnect reliability besides
the alloying element silver. In this paper, the incorporation, the distribution and the chemical state of sulfur in Cu(Ag)
films is discussed in dependence on the thermal history. The investigations were mainly carried out by XPS and GD-OES measurements. 相似文献
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天然杂质对闪锌矿电子结构和半导体性质的影响 总被引:1,自引:0,他引:1
采用密度泛函理论系统研究了分别含有十四种天然杂质的闪锌矿的电子结构,并讨论了这十四种杂质对闪锌矿半导体性质的影响.研究结果表明,锰、铁、钴、镍、铜、镉、汞、银、铅、锑杂质的存在使闪锌矿的带隙变窄,导致吸收带边增大.除了镉和汞杂质外,其余杂质的存在均导致费米能级向高能级方向移动,并且在闪锌矿禁带中产生了杂质能级.铁、镓、锗、铟、锡、锑杂质使闪锌矿的半导体类型由p型变为n型;而锰、钴、镍、铜、镉、汞、银、铅杂质对闪锌矿的半导体类型没有影响.铜杂质使闪锌矿由直接带隙变为间接带隙半导体. 相似文献
5.
Johannes Bitzer Steffen Otterbach Kavipriya Thangavel Anastasia Kultaeva Prof. Dr. Rochus Schmid Prof. Dr. Andreas Pöppl Prof. Dr. Wolfgang Kleist 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(25):5667-5675
Metal–organic frameworks containing multiple metals distributed over crystallographically equivalent framework positions (mixed-metal MOFs) represent an interesting class of materials, since the close vicinity of isolated metal centers often gives rise to synergistic effects. However, appropriate characterization techniques for detailed investigations of these mixed-metal metal–organic framework materials, particularly addressing the distribution of metals within the lattice, are rarely available. The synthesis of mixed-metal FeCuBTC materials in direct syntheses proved to be difficult and only a thorough characterization using various techniques, like powder X-ray diffraction, X-ray absorption spectroscopy and electron paramagnetic resonance spectroscopy, unambiguously evidenced the formation of a mixed-metal FeCuBTC material with HKUST-1 structure, which contained bimetallic Fe−Cu paddlewheels as well as monometallic Cu−Cu and Fe−Fe units under optimized synthesis conditions. The in-depth characterization showed that other synthetic procedures led to impurities, which contained the majority of the applied iron and were impossible or difficult to identify using solely standard characterization techniques. Therefore, this study shows the necessity to characterize mixed-metal MOFs extensively to unambiguously prove the incorporation of both metals at the desired positions. The controlled positioning of metal centers in mixed-metal metal–organic framework materials and the thorough characterization thereof is particularly important to derive structure–property or structure–activity correlations. 相似文献
6.
In post-CMP (chemical mechanical polishing) processing, the use of poly vinyl acetal (PVA) brushes to clean the wafer surface is one of the most effective and prominent techniques applied for the removal of CMP contaminants. Recently, organic contaminants induced in different types of PVA brushes during brush manufacturing have been drawing substantial research interest in CMP communities. In this study, investigated the root cause of these residual organic impurities in two different types of PVA brushes was investigated: roller and pencil type brushes. PVA roller brushes have a skin layer due to the brush molding process, but pencil-type PVA brushes do not have the skin layer. Extraction of organic impurities from both types of brushes was accomplished using an ultrasound-assisted technique at a sonication frequency of 40 kHz, and input power of 600 W. Further evaluation of these organic impurities using Field Emission Scanning Electron Microscopy (FE-SEM) revealed a large number of organic impurities in roller brushes and negligible impurities in pencil brushes. Time of flight secondary ion mass spectrometry (TOF-SIMS) analysis confirmed polydimethylsiloxane (PDMS) as the organic impurities extracted from PVA roller brushes, which were generated during the brush manufacturing process. The PDMS content in PVA roller brushes was further analyzed using FE-SEM micrographs via dissolving the organic impurities in tetramethylammonium hydroxide solution (TMAH). During brush fabrication, the high content of PDMS organic impurities in roller PVA brushes is essentially attributed to the presence of the additional skin layer formed by the mold releasing agent at the mold-cavity interface. 相似文献
7.
《Analytical letters》2012,45(7):671-676
Abstract The method of electrolytic dissolution in organic solvents (saturated with NH1Cl) followed by atomic absorption spectroscopy was applied to the determination of Fe and Cu impurities in niobium metal. It was found that a previously reported decrease in sensitivity could be attributed to precipitation of NH4Cl on the walls of the feeding chamber of the spectrometer and could be avoided by diluting the solution before measurement. 相似文献
8.
The application of Fe@FexOy nanoparticles was examined for the sequestration of catalytic metal impurities from organic reaction products. An X-ray photoelectron spectroscopy (XPS) study of the recovered particles confirmed Fe@FexOy sequestered Co2+, Cu2+, Ni2+, RhX+, Pd2+, Ag+, and Pt4+ by coordination of the metal ion to the iron oxide surfaces and followed by subsequent reduction of the surface-bonded ions to their metallic state. Fe@FexOy metal sequestration was found to be effective for catalyst impurities in the absence of strongly coordinating environments but was inhibited by the presence of phosphines. Sequestration of phosphine-coordinated metal impurities was achieved through the addition of either cysteamine or 3-mercaptopropionic acid to the Fe@FexOy during sequestration. This approach was applied to model syntheses using Grubbs' Catalyst (first generation), Pd(PPh3)4, Pd2(dba)3, and Wilkinson's Catalyst (RhCl(PPh3)3). 相似文献
9.
Hye-Young Chung Sang-Hak Lee Young-Hun Kim Ki-Sang Lee Dae-Hong Kim 《Analytical sciences》2003,19(7):1051-1054
An etching technique for the determination of the metallic impurities distribution in silicon wafers has been developed. An area of 10 mmphi and 10 microm depth was etched by 100 microL of an etching solution with a HF and HNO3 mixture. The acid matrix was evaporated on the wafer surface by IR lamp illumination and vacuum exhaust. Metallic impurities remaining on the wafer surface were redissolved into the collection solution, which was measured by electrothermal atomic absorption spectrometry (ET-AAS). The recovery invested by local etching/ET-AAS was within 95 - 112% for Fe, Cu and Ni. The detection limit (3sigma) for Fe, Cu and Ni in silicon was 1 x 10(13) atoms/cm3. To confirm the applicability, local etching was applied to evaluate the effects of metallic impurities in a gettering study and the electronic properties of semiconductor devices. It was found that local etching is a useful sample preparation technique for the analysis of metallic impurities in a specific area on a silicon wafer. 相似文献
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Siyavash Kazemi Movahed Parinaz Salari Melika Kasmaei Mahsa Armaghan Minoo Dabiri Mostafa M. Amini 《应用有机金属化学》2018,32(1)
Cu nanoparticles with average particles size around 10 nm were incorporated on the surface of a mesoporous carbon nitride support. The XRD and N2 adsorption isotherms show that it maintains a hexagonal mesoporous structure with a high surface area (600.03 m2 g?1). The embedded Cu nanoparticles exhibit extremely high catalytic performance in two different kinds of organic reactions. The Huisgen 1,3‐dipolar cycloaddition and N‐arylation of N‐heterocycles were all accomplished. 相似文献
12.
The improved determination of both iron and copper in red and white wines has been developed which avoids the preliminary process of ashing the sample before processing the ash for the actual evaluation of these two troublesome impurities. The new procedure employs bathocuproine and bathophcnanthroline as completing ligands with spectrophotometric determination of the Cu and the Fe in situ. The new method is economical in required analysis time, manipulative details and in quantity of sample involved. It has been shown that the new method is comparable in accuracy to previous published procedures, and as control analyses substitute wet ashing technique, the HNO3-HCIO4 destruction of organic matter, was applied. 相似文献
13.
研究了用ICP-AES法测定松树脂中的铁、铅、铜、锌、铝的方法,确定了松树脂中杂质元素同时测定的最佳工作条件.并对实际样品用 ICP- AES与AAS法对比试验,回收率在91%-104%之间,结果令人满意。该法快速、简便、可靠,适用于出口松树脂的日常检验。 相似文献
14.
色谱分离ICP-AES法测定高纯度八氧化三铀中的13种微量杂质 总被引:1,自引:0,他引:1
采用磷酸三丁酯(TBP)萃淋树脂色层分离铀,用电感耦合等离子体-原子发射光谱法测定分离后的离纯度铀氧化物的杂质元素Al、Ca、Cr、Cu、Fu、Mn、Mo、Ni、P、Ti、V、Zn、Zr,除Al、Fe、Mo外的其余10种元素的测定结果符合标准物质定值的要求。 相似文献
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16.
HPLC测定葡萄糖酸盐的研究 总被引:4,自引:0,他引:4
首次应用HPLC测定发酵法制葡萄糖酸盐产品的质量,研究了不同色谱体系、流动相酸度对葡萄糖酸盐分离的影响;测定了多种葡萄糖酸盐(钠盐、钾盐、锌盐、锰盐、镁盐)并在所测样品中成功地分离出多个有机杂质;应用二极管阵列检测器(PAD)对样品中杂质的来源和结构进行了初步研究;讨论了葡萄糖酸盐的现行化学测定法与液相色谱测定法之间的差异。本法简便、快速、准确 相似文献
17.
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
18.
S. Niese 《Journal of Radioanalytical and Nuclear Chemistry》1982,72(1-2):9-16
Using a layer etching technique impurity profiles of Cu and Fe in silicon samples are measured by n.a.a. Radiation enhanced
diffusion of Cu and Fe impurities from the surface into the bulk material has been observed. The samples were etched before
irradiation to remove the impurity profiles caused by the sampling procedures. 相似文献
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Szanyi J Daturi M Clet G Baer DR Peden CH 《Physical chemistry chemical physics : PCCP》2012,14(13):4383-4390
Cu-BTC (also known as HKUST-1) is a well-characterized metal-organic framework material produced in an industrial scale and widely studied for a number of potential applications by the scientific community. The co-existence of Cu(+) and Cu(2+) entities has already been observed in this material, but the presence of Cu(+) ions was attributed to oxide impurities. The results presented here clearly demonstrate that Cu(+) ions can be present in high concentrations inside the hybrid structure. Furthermore, switching between the two copper oxidation states can be induced by redox treatments, using vacuum and/or reducing gases at different sample temperatures. 相似文献