共查询到19条相似文献,搜索用时 109 毫秒
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在纳米Cu-ZnO上仲丁醇的催化脱氢 总被引:7,自引:0,他引:7
Cu- Zn O催化剂在醇类脱氢反应、甲醇合成和酯类氢解等催化反应中有着广泛的应用 [1~ 4 ] ,但将其应用于丁醇脱氢反应的报道较少[5,6] .本工作制备了纳米铜和纳米氧化锌 ,并采用超声方法制备了纳米铜和纳米氧化锌的混合催化剂 ,考察了 3种催化剂在仲丁醇脱氢制备甲基乙基酮 (MEK)反应中的催化活性 .反应结果表明 ,与单独的纳米铜和纳米氧化锌相比 ,混合催化剂不但保持了较高的脱氢活性 ,且使反应的稳定性大大提高 .对催化剂的 XRD,BET和 EPR研究结果表明 ,Zn O起到分散和稳定 Cu粒子的作用 ,铜和氧化锌之间存在某种相互作用 .1 实… 相似文献
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纳米氧化锌在模拟煤气下吸附单质汞的实验研究 总被引:1,自引:0,他引:1
纳米氧化锌在模拟煤气下吸附单质汞的实验研究 《燃料化学学报》2013,41(11):1371-1377
采用均匀沉淀法制备纳米氧化锌吸附剂,并采用BET、XRD、XPS等分析手段对其进行表征。在固定床吸附实验台上,研究了吸附剂在N2和模拟煤气气氛下对单质汞的吸附特性,分析气体成分对纳米氧化锌脱汞性能的影响。结果表明,纳米氧化锌在纯N2气氛下的脱汞效率较低,以物理吸附为主;H2S的加入可以显著提高纳米氧化锌对汞的吸附,停止通入H2S后,脱汞效率仍能维持较长时间;CO和H2通过促进纳米氧化锌脱硫进而促进对汞的脱除。随着温度的提高,纳米氧化锌表面形成的单质硫逐渐减少,抑制了吸附剂对单质汞的吸附脱除。 相似文献
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以介孔氧化硅薄膜为模板电沉积合成新型纳米结构 总被引:6,自引:0,他引:6
首次以不同孔道结构的介孔氧化硅薄膜为模板,采用电化学沉积的方法,合成了金属铜和半导体氧化锌的纳米材料,并对其结构进行了表征.以六方孔道结构的介孔氧化硅模板获得了直径为7nm的金属铜纳米线阵列;以笼状体心立方孔道结构的模板获得了具有哑铃状形貌的铜单质纳米颗粒.对于氧化锌纳米结构,电化学沉积过程使得氧化锌完全填充氧化硅模板的孔道,分别得到了具有六方和体心立方介孔结构的Zn0/SiO2纳米复合物薄膜. 相似文献
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以三聚磷酸钠为表面活性剂,采用水热合成法制备了氧化锌纳米片。采用场发射扫描电镜,透射电镜,紫外可见分光光度计和荧光光谱仪对氧化锌纳米片的显微结构和光学性能进行了表征,并对氧化锌纳米片的形成机理进行了探讨。结果表明:在220 ℃水热反应28 h可得到尺寸大约为600 nm × 500 nm × 50 nm(长×宽×高)结晶良好的六角形氧化锌纳米片,氧化锌纳米片对可见光的反射率超过90%,对紫外光的反射率小于20%,在395 nm附近均存在较强的紫外发射峰。氧化锌纳米片的形成是由于氧化锌晶体的正极面{001}晶面上显露的OH-悬健部分被具有负电性的磷酸根取代,这种取代的发生,阻碍了溶液中的生长基元Zn(OH)42-在该晶面上叠合,使得本应生长最快的(001)晶面生长受限,所以得到了片状的纳米氧化锌。 相似文献
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通过简单研磨实现固相反应的方法制备了纳米氧化锌材料,并利用石墨烯掺杂对氧化锌进行改性,研究了氧化锌材料的气敏性能。利用X射线衍射仪(XRD)、扫描电镜(SEM)、红外光谱仪(IR)对合成的样品进行了结构和形貌表征,考察了原料比例和石墨烯掺杂量对氧化锌形貌和气敏性能的影响。结果表明:合成的氧化锌均为纳米颗粒,随着柠檬酸量增加,得到许多有气孔的氧化锌;石墨烯掺杂后,均得到纳米颗粒的氧化锌;气体检测表明,石墨烯掺杂后的氧化锌,其最佳工作温度由400℃降为280℃,对三乙胺表现出较高的选择性;掺杂3%石墨烯的氧化锌对浓度为0.1 mmol/L三乙胺的响应值(S=Ra/Rg)达到18,是掺杂前的4倍。石墨烯掺杂纳米ZnO可作为检测三乙胺气体的新型传感材料。 相似文献
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以醋酸锌和膨胀石墨为原料, 采用真空辅助压力诱导手段使反应溶液注入膨胀石墨层间, 在180℃下溶剂热反应12 h, 一步得到氧化锌纳米棒/石墨烯复合光催化剂, 采用X射线衍射仪(XRD)和透射电子显微镜(TEM)等对复合光催化剂的结构和形貌进行了表征. 结果表明, 合成的氧化锌纳米棒具有六方晶系纤锌矿结构; 氧化锌纳米棒在石墨烯表面分散性较好, 其平均直径约50 nm, 长度约150~200 nm. 所得氧化锌纳米棒/石墨烯复合材料对亚甲基蓝的降解效率优于目前应用最广泛的光催化剂Degussa P25. 相似文献
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MK Talari AB Abdul Majeed DK Tripathi M Tripathy 《Chemical & pharmaceutical bulletin》2012,60(7):818-824
The application of nanomaterials has gained considerable momentum in various fields in recent years due to their high reactivity, excellent surface properties and quantum effects in the nanometer range. The properties of zinc oxide (ZnO) vary with its crystallite size or particle size and often nanocrystalline ZnO is seen to exhibit superior physical and chemical properties due to their higher surface area and modified electronic structure. ZnO nanoparticles are reported to exhibit strong bacterial inhibiting activity and silver (Ag) has been extensively used for its antimicrobial properties since ages. In this study, Ag doped ZnO nanoparticles were synthesized by mechanochemical processing in a high energy ball mill and investigated for antimicrobial activity. The nanocrystalline nature of zinc oxide was established by X-ray diffraction (XRD) studies. It is seen from the XRD data obtained from the samples, that crystallite size of the zinc oxide nanoparticles is seen to decrease with increasing Ag addition. Field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) data also supported the nanoparticle formation during the synthesis. The doped nanoparticles were subjected to antimicrobial investigation and found that both increase in Ag content and decrease in particle size contributed significantly towards antimicrobial efficiency. It was also observed that Ag doped ZnO nanoparticles possess enhanced antimicrobial potential than that of virgin ZnO against the studied microorganisms of Escherichia coli and Staphylococcus aureus. 相似文献
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A procedure is described for the determination of zinc by amperomctric titration with potassium ferrocyanide. The reaction is carried out in a solution heated to approximately 65° C to obtain reproducible results. The method is suitable for application to a variety of zinc-containing materials including those of high zinc content. It gives satisfactory results on materials such as purified zinc oxide, slab zinc, ores, and flue dusts. 相似文献
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从氧化锌矿制备高纯超细ZnO粉体 总被引:7,自引:0,他引:7
超细ZnO具有表面效应、体积效应、久保效应以及优良的光活性、电活性、烧结活性和催化活性 ,可用来制造气体传感器、荧光体、紫外线遮蔽材料、变阻器、图像记录材料、压电材料、压敏电阻、高效催化剂、磁性材料、陶瓷材料、化妆品及医药材料。在橡胶工业、染料油墨等领域也有应用前景[1~ 5] 。目前 ,国内外对制备超细ZnO粉体的研究文章较多 ,但以氧化锌矿为原料直接研制的文章还很少。湿化学法是近二十年来超细ZnO产品应用开发的主要活跃点之一 ,直接沉淀法是制备超细ZnO的一种重要湿化学方法 ,它是在含有一种或多种粒子的可溶… 相似文献
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超疏水-超疏油材料在防污、防水、防油等领域有广泛的应用前景而引起人们极度关注。 本文用全氟辛酸溶液浸泡锌粉制得超疏水-超疏油锌粉,用聚乙烯醇胶将超疏水-超疏油锌粉粘合、固定到玻璃、木头、塑料、不锈钢、纸片、石头表面后可制得超疏水-超疏油表面,水滴、油滴在其表面的接触角均超过150°。 锌粉与全氟辛酸反应后生成Zn[CF3(CF2)6COO]2,氟代长链烷基的低表面能化学组成与微纳米粗糙结构的协调作用使其表现出超疏水、超疏油性能。 相关研究有望为超双疏材料的设计、制备及其在自清洁、防水防油及抗污等领域的应用提供借鉴。 相似文献
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Maryam Bayat Meisam Zargar Tamara Astarkhanova Elena Pakina Sergey Ladan Marina Lyashko Sergey I. Shkurkin 《Molecules (Basel, Switzerland)》2021,26(10)
In this investigation, for the first time, we used Fragaria ananassa (strawberry) leaf extract as a source of natural reducing, capping or stabilizing agents to develop an eco-friendly, cost-effective and safe process for the biosynthesis of metal-based nanoparticles including silver, copper, iron, zinc and magnesium oxide. Calcinated and non-calcinated zinc oxide nanoparticles also synthesized during a method different from our previous study. To confirm the successful formation of nanoparticles, different characterization techniques applied. UV-Vis spectroscopy, X-ray Diffraction (XRD) spectroscopy, Field Emission Scanning Electron Microscopy (FESEM) coupled with Energy Dispersive X-ray Spectroscopy (EDS), Photon Cross-Correlation Spectroscopy (PCCS) and Fourier Transformed Infrared Spectroscopy (FT-IR) were used to study the unique structure and properties of biosynthesized nanoparticles. The results show the successful formation of metal-based particles in the range of nanometer, confirmed by different characterization techniques. Finally, the presented approach has been demonstrated to be effective in the biosynthesis of metal and metal oxide nanoparticles. 相似文献
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Zinc has been widely utilized as an antimicrobial material, often in the form of complexes or zinc oxide nanoparticles. The efficacy of zinc complexes are often due to the synergistic effect of both the zinc ions and the attached organic ligands. In contrast, the nanoparticle effect of ZnO, and the photocatalytic generation of reactive oxygen species (ROS) has been postulated to be the effective mechanism of ZnO as a biocide. Recently, new forms of zinc-based biocidal materials have been reported with distinct antimicrobial mechanisms. This minireview summarizes these recent advances, including zinc-based nano-arrays, MOF-based ROS release and zinc composites that can self-generate ROS. 相似文献
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采用氯化铵-氨水体系溶解试样,干过滤后,向移取的滤液中加入氯化钡和硫酸共沉淀铅离子,过滤分离硫酸铅沉淀,向滤液中加人抗坏血酸、氟化钾、硫代硫酸钠等掩蔽剂掩蔽少量干扰元素。在pH=5~6的乙酸-乙酸钠缓冲溶液中,以二甲酚橙为指示剂,用EDTA标准滴定溶液滴定测得结果为氧化锌、水溶性锌和镉合量,扣除由原子吸收光谱法测得的水溶性锌量和镉量,即为氧化锌量。对总氨浓度、氯化铵-氨水浓度比、溶液加入量、搅拌时间、共存离子干扰、精密度等进行了实验,建立了EDTA滴定法测定含锌物料中氧化锌物相的分析方法。实验证明,氧化锌含量在24%~83%时,方法精密度(RSD)为0.25%~0.54%,加标回收率在99%~104%,完全满足含锌物料中氧化锌的测定要求。 相似文献