共查询到18条相似文献,搜索用时 125 毫秒
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通过溶胶和超临界干燥方法制得了Fe2O3/Al2O3二元气凝胶,其比表面积和孔隙体积分别为246 m2·g-1和1.89 cm3·g-1,并具有较宽的孔径分布。以Fe2O3/Al2O3二元气凝胶作催化剂,通过甲烷催化裂解成功地合成了高质量的单壁纳米碳管。利用FESEM、TEM和HRTEM、Raman光谱等分析手段研究了反应温度对单壁纳米碳管生长的影响。结果表明在900 ℃时合成单壁纳米碳管的质量较高,并且合成的炭产物为毡状,该炭产物主要为高质量的单壁纳米碳管。 相似文献
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采用共沉淀法合成Fe3O4纳米粒子, 将含有硅氧烷基的离子型改性剂二甲基十八烷基氯化铵与Fe3O4纳米粒子进行接枝反应, 再用脂肪醇聚氧乙烯醚磺酸盐的长链阴离子交换Cl-, 在Fe3O4纳米粒子表面生成具有阴、 阳离子双电层结构的表面处理层, 得到无溶剂Fe3O4纳米流体. 研究结果表明, 在Fe3O4纳米粒子表面成功接枝了有机物长链, 改性的Fe3O4纳米粒子呈单分散分布, 其损耗剪切模量G″明显大于储能剪切模量G', 具有明显的流体行为, 在室温下即可流动. 相似文献
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碳纳米管负载的Fe2O3催化剂制备 总被引:4,自引:0,他引:4
Carbon nanotubes were modified by FeSO4-H2O2 system, iron hydroxides were adsorbed on the wall of carbon nanotubes simultaneously. These precursors were treated at 723K for 2 h under hydrogen, nitrogen and air atmosphere to prepare carbon nanotubes supported γ-Fe2O3catalyst, γ-Fe2O3and α-Fe2O3compound catalyst and amorphous Fe2O3catalyst, respectively. This is green method to prepare high Fe2O3loading (≥50 %) catalyst without adding other cation. The different structures Fe2O3catalysts can be synthesized by controlling the condition of thermal treatment to content active phase requirements for different catalytic reactions. The paper presents a new method to prepare carbon nanotubes supported catalysts. 相似文献
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球形纳米Fe3O4的制备及超级电容性能研究 总被引:2,自引:0,他引:2
采用双氧水氧化水热法制备Fe3O4,通过IR、XRD和SEM对样品的结构和性能进行表征。结果表明,产物为形貌规整的球形,平均粒径为25 nm。通过恒流充放电、循环伏安和交流阻抗等方法研究Fe3O4电极的电容性能。电化学测试表明,在1 mol·L-1 Na2SO3溶液中,-1.2~0.2 V(vs SCE)电位范围内,Fe3O相似文献
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首次采用简单的一锅法制备了Fe2O3/Fe2TiO5异质结纳米材料。构建S型异质结后,与纯的Fe2O3和Fe2TiO5相比,Fe2O3/Fe2TiO5复合材料表现出更高的光催化降解速率和效率。经过2.5 h的光照后,Fe2O3/Fe2TiO5可以降解接近100%的亚甲基蓝(MB)。在Fe2O3/Fe2TiO5复合材料中,Fe2O3和Fe2TiO5之间形成了内建电场,可以促进光生电子-空穴对的分离。因此,具有更高能量的Fe2TiO5导带中的电子和具有更高能量的Fe2O3价带中的空穴可以得到有效的保留,从而使它们更加有效地扩散到催化剂表面,并参加降解反应。此外,Fe2O3/Fe2TiO5复合材料具有很好的光催化稳定性。 相似文献
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固定n(Ce)/n(Zr)比为0.67/0.33,用共沉淀法制得一系列CeO2-ZrO2-Al2O3固溶体.采用这些固溶体作载体,以Fe2O3为活性组分,用浸渍法制备了一系列催化剂.BET结果显示,将适量Ce0.67Zr0.33O2引入到Al2O3载体中有助于催化剂保持较高的比表面积.TPR结果显示,载体中引入适量的Ce0.67Zr0.33O2可以改善催化剂的氧化还原性能.XRD结果表明,Fe2O3在CeO2-ZrO2-Al2O3载体上呈现出良好的分散状况,老化前后催化剂的晶相结构基本无明显变化.特别是当载体中m(Ce0.67Zr0.33O2)∶m(Al2O3)的值为1∶2时,Fe2O3/CeO2-ZrO2-Al2O3催化剂在甲烷催化燃烧中显示出最佳的催化性能和抗高温老化性能. 相似文献
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乙烯在纳米催化剂InVO4-TiO2上的可见光降解 总被引:1,自引:0,他引:1
The InVO4-TiO2 nano-crystalline photocatalyst was prepared by sol-gel method and characterized by DRS, FTIR, Raman and XRD. The photocatalytic activities of the prepared sample were investigated by photocatalytic degradation of ethylene in the gaseous phase under visible light irradiation (λ>450 nm). The results indicate that both of pure TiO2 and InVO4 or their simple mixture show no photocatalytic activities for degradation of ethylene under visible light irradiation. However, as-synthesized InVO4-TiO2 catalyzes the degradation of ethylene into CO2 under visible light irradiation. In addition, the interaction between InVO4 and TiO2 results in some structural distortion to all the crystal forms of TiO2 in as-synthesized catalyst InVO4-TiO2. 相似文献
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用一种方法成功合成出了球体、四方体、八面体、不规则多面体、三角形和不规则颗粒等六种具有不同形貌的Fe3O4纳米粒子,通过扫描电子显微镜(SEM)表征了粒子形貌。试样经过X-射线衍射(XRD)表征具有尖晶石结构,且结晶良好。经震动样品磁强计(VSM)测定,各种形貌的Fe3O4纳米粒子都具有良好的磁性,其中八面体形貌的Fe3O4纳米粒子的饱和磁化强度达到86.56 emu·g-1,剩磁为10.64 emu·g-1,矫顽力为138 Oe。讨论了不同形貌的Fe3O4纳米粒子的形成机制,得出了晶核的生长环境对纳米粒子的形貌有重要影响的结论。 相似文献
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采用三种低温溶胶-凝胶法制备了具有不同Fe3O4掺杂量的磁靶向纳米Fe3O4-TiO2复合物, 通过X射线衍射(XRD)、透射电镜(TEM)、傅里叶变换红外(FTIR)光谱、紫外-可见(UV-Vis)光谱、荧光光谱(FS)及磁性能分析等表征方法筛选出包覆均匀、分散性好、磁性能优异及光催化活性较高的纳米Fe3O4-TiO2复合物. 以四甲基偶氮唑蓝(MTT)法检测肝癌细胞(HepG2)的存活率, 考察纳米Fe3O4-TiO2复合物在外磁场作用下对HepG2 细胞的光催化杀伤效应. 结果表明: 采用方法三制备的5%(质量分数)Fe3O4-TiO2复合物具备核-壳结构, 在混悬液中分散性较好, 平均粒径约为50 nm, 具有较强的光催化活性和良好的磁响应性, 同时将纳米TiO2的光响应范围拓宽至444 nm; 在外磁场作用下, 紫外光和可见光激发纳米Fe3O4-TiO2复合物对HepG2细胞的杀伤效应差异不大, 且均强于纳米TiO2; 其杀伤效应在0-1.0 T范围内随着外磁场强度的增大而增强. 相似文献
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通过静电纺丝法制备了含有Fe3O4纳米粒子的TiO2纳米纤维,采用水热法对该纤维表面进行纳米Ag修饰,制备出具有较强磁性和较好光催化性能的复合纤维.采用X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)和紫外-可见光谱(UV-Vis)等对样品的结构和形貌进行表征,并以罗丹明B(Rh B)水溶液降解为模型反应,考察样品在紫外光照射下的光催化性能.结果表明,所制备的TiO2为锐钛矿结构,Fe3O4纳米粒子均匀分布在TiO2纤维中,Ag纳米颗粒比较均匀地分散在磁性TiO2纤维表面.经过纳米Ag修饰后,材料的光吸收能力大为增强,吸收带红移并扩展到可见光区.在紫外光照射40 min后,合成样品对Rh B的降解率达到99.5%.此外,Fe3O4纳米粒子的存在使该材料具有较强的磁性,可通过外加磁场将其分离回收. 相似文献
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聚乙烯基胺包裹Fe3O4@SiO2磁性微球用于Knoevenagel缩合(英文)简 总被引:1,自引:0,他引:1
Polyvinyl amine coated Fe3O4@SiO2 composite microspheres with a core-shell structure were prepared and employed as a magnetic catalyst for Knoevenagel condensation under mild conditions. The catalyst can be readily recovered using a magnet and reused several times without loss in activity or selectivity. The performance of the magnetic base catalyst was compared with that of polyvinyl amine functionalized mesoporous SBA-15, which showed that the magnetic nanoparticles gave improved reaction rate and yield. 相似文献
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采用超声法将磁基体Fe3O4和BiVO4复合,制备了易于固液分离的磁性可见光催化剂BiVO4/Fe3O4。采用X射线衍射(XRD)、傅立叶转换红外光谱(FTIR)、紫外-可见漫反射光谱(DRS)、透射电子显微镜(TEM)和磁学性质测量系统(MPMS)对产物进行了表征,并以亚甲基蓝为目标降解物,考察了BiVO4/Fe3O4的可见光催化活性。当BiVO4与Fe3O4质量比为5:1时,BiVO4/Fe3O4的催化活性最高,反应经过5 h,对亚甲基蓝的降解率达到92.0%,而单独使用BiVO4为催化剂,降解率仅为72.5%。这表明Fe3O4不仅起到磁基体的作用,还起到助催化剂的作用。BiVO4/Fe3O4在外加磁场的作用下很容易被分离,撤消外加磁场后,通过搅拌又可重新分散。BiVO4/Fe3O4 3次回收后的降解率仍高于80%。 相似文献
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磁性Fe3O4 /壳聚糖的化学修饰及包覆机理研究 总被引:1,自引:0,他引:1
Nano-sized Fe3O4 powder was prepared through an Oxygenation-Hydrothermal method. The chitosan magnetic complex was prepared by coating chitosan on the surface of Fe3O4 powders through Microlatex-Crosslinking Method. The product was characterized by IR, XRD, TEM, Vibrating Sample Magnetometer (VSM), TG methods. Results show that the as-prepared powder is 25 nm in size and shows supermagnetism. The content of magnetite in microspheres is 37.8%. The mechanism for the coating reaction of chitosan to Fe3O4 nanoparticles is also suggested. 相似文献
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Polyaniline (PANI) nanotubes containing Fe3O4 nanoparticles were synthesized under ultrasonic irradiation of the aqueous solutions of aniline, ammonium peroxydisulfate (APS), phosphoric acid (H3PO4), and the quantitative amount of Fe3O4. It was found that the obtained samples had the morphologies of nanotubes. TEM images and selected area electronic diffractions showed that Fe3O4 nanoparticles were embedded in PANI nanotubes. We thought that the mechanism of the formation of PANI/Fe3O4 nanotubes could be attributed to the ultrasonic irradiation and the H3PO4-aniline salt template. The molecular structure of PANI/Fe3O4 nanotubes were characterized by Fourier transform infrared spectroscopy (FTIR), UV-vis absorption spectra and X-ray diffraction (XRD). The conductivity and magnetic properties of the PANI nanotubes containing Fe3O4 nanoparticles were also investigated. 相似文献