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SBA-15介孔分子筛担载的钒基氧化物催化剂对乙烷选择氧化性能 总被引:1,自引:0,他引:1
用等体积浸渍法制备了SBA-15担载的钒基(V/SBA-15)和钾修饰的钒基氧化物(K-V/SBA-15)催化剂, 使用氮气吸附、小角X射线衍射(XRD)、紫外-可见漫反射光谱(UV-Vis DRS)和紫外激光拉曼光谱对这些催化剂的结构进行表征, 并评价了这些催化剂对乙烷选择氧化的活性与选择性. 实验结果表明介孔结构SBA-15对乙烷选择氧化的活性优于常规的SiO2; 对于SBA-15担载的V/SBA-15和K-V/SBA-15催化剂, 极低钒担载量(nV:nSi≤0.1:100)时隔离的四配位钒氧化物是乙烷选择氧化生成醛类化合物的活性物种, 高钒担载量(nV:nSi≥2.5:100)时聚合的和微晶态的钒氧化物是乙烷氧化脱氢或深度氧化的活性物种. 相似文献
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V-P-O/TiO~2-SiO~2催化剂的制备、表征及其在丙烷氧化制取丙 烯酸反应中的应 用研究 总被引:3,自引:0,他引:3
通过湿磨法,将钒-磷-氧(V-P-O)氧化物负载于钛硅干凝胶(TiO~2-SiO~2)上,制备了V-P-O/TiO~2-SiO~2氧化物催化剂,并运用BET,XRD,TEM及XPS等技术考察了润湿剂,V-P-O的含量及焙烧条件对催化剂结构的影响。由BET方法发现,以异丁醇为润湿剂对催化剂表面积影响较小。XRD和TEM考察结果表明,所制备的催化剂有较高的热稳定性。通过XPS分析,证实钒元素主要以V(IV)价态存在于催化剂的表面。V-P-O/TiO~2-SiO~2催化剂在丙烷氧化反应中显示了良好的催化性能。 相似文献
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通过湿磨法,将钒-磷-氧(V-P-O)氧化物负载于钛硅干凝胶(TiO_2-SiO_2)上,制备了V-P-O/TiO_2-SiO_2氧化物催化剂,并运用BET,XRD,TEM及XPS等技术考察了润湿剂,V-P-O的含量及焙烧条件对催化剂结构的影响.由BET方法发现,以异丁醇为润湿剂对催化剂表面积影响较小.XRD和TEM考察结果表明,所制备的催化剂有较高的热稳定性.通过XPS分析,证实钒元素主要以V(Ⅳ)价态存在于催化剂的表面.V-P-O/TiO_2-SiO_2催化剂在丙烷氧化反应中显示了良好的催化性能. 相似文献
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钟华 《中国无机分析化学》2013,3(2):56-59
对脉冲加热-红外吸收法测定钒铝合金中氢的分析方法进行了研究。通过实验对分析功率、称样量和校正标样等测试条件进行了讨论。实验表明钒铝合金中的氢易释放,对于AlV85样品中氢,热提取法和熔融法测定结果一致;但AlV50样品中氢,热提取法的结果略高于熔融法,故实验中选用热提取法测定钒铝合金中氢量。热提取法用0.75g金属锡作助熔剂,于4.0kW分析功率条件下测定钛标准样品中氢来确定氢工作曲线的校正系数,在1.5kW分析功率下测定钒铝合金中氢,测定结果与高频感应-热导法(用5g钢标准样品对氢的测定进行校正)结果吻合。对3个钒铝合金中氢量进行了测定,结果的相对标准偏差为2.2%~6.5%(n=8)。 相似文献
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金属卟啉是一种重要的金属-有机复合物,在光电转换器件、催化、传感、医学等领域有着广阔的应用前景。对无机二维纳米材料(石墨烯或过渡金属硫属化合物等)的广泛研究促使金属-有机二维纳米材料成为当前的研究热点之一。本文针对金属-有机以及卟啉二维纳米材料的研究现状,在简要回顾金属-有机二维纳米材料发展历史的基础上,详细总结了金属卟啉单分散二维纳米晶和二维薄膜的制备方法,综述了其当前在太阳能电池、光电催化以及光学传感等方面的应用,最后讨论了金属卟啉二维纳米材料当前面临的研究问题及未来可能的发展方向。 相似文献
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由于聚合物膜具有可高度设计、机械性能好、易于加工 等优点,是理想的气体分离材料。然而,聚合物膜在气体选择性和渗透性方面存在平衡限制,在聚合物中引入纳米粒子,是提高气体分离性能的一种有效手段。本文基于聚合物/无机纳米粒子复合膜在气体分离领域的研究现状,重点阐述了零维纳米粒子(二氧化硅、二氧化钛)、一维纳米粒子(碳纳米管)、二维纳米粒子(氧化石墨烯、二维过渡金属氧化物)、三维纳米粒子(金属有机框架、沸石)对气体分离性能的影响,并展望了聚合物复合分离膜的发展趋势,为未来高效分离膜的研发提供了参考。 相似文献
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采用微机械剥离法得到横向尺寸为10 μm的碲化锗(GeTe)纳米片. 通过电子束曝光和真空溅射镀膜的方法, 以钛金合金为接触电极, 制备基于二维碲化锗(2D-GeTe)纳米材料的场效应晶体管(FET), 并测定了其电学性能. 结果表明, 剥离所得GeTe纳米材料具有良好的结晶性, 光学带隙为1.98 eV, 属于p型半导体; 该场效应晶体管展现出了6.4 cm2·V?1·s?1的载流子迁移率和670的开关电流比的良好电学性能. 相似文献
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Xiaoding Lou 《中国化学快报》2019,30(9):1557-1564
The complexity of biological samples determines that the detection of a single biomolecule is unable to satisfy actual needs. Moreover, the “false positives” results caused by a single biomolecule detections easily leads to erroneous clinical diagnosis and treatment. Thus, it is important for the homogenous quantification of multiple biomolecules in not only basic research but also practical application. As a consequent, a large number of literatures have been exploited to monitor multiple biomolecules in homogenous solution, enabling facilitating the development of the disease diagnosis, treatment as well as drug discovery. One-dimensional nanomaterials and two-dimensional nanomaterials have special physical and chemical properties, such as good electrochemical properties, stable structure, large specific surface area, and biocompatibility, which are widely used in electrochemical and fluorescent detection of biomolecules. This tutorial review highlights the recent development for the detection of multiple biomolecules by using nanomaterials including one-dimensional materials (1DMs) as well as two-dimensional materials (2DMs). 相似文献
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Wei Cai Bi-Bo Wang Xin Wang Yu-Lu Zhu Zhao-Xin Li Zhou-Mei Xu Lei Song Wei-Zhao Hu Yuan Hu 《高分子科学》2021,39(8):935-956
The high fire safety of polymer nanocomposites is being pursued by research institutions around the world. In addition to intrinsic flame retardancy strategy, the additive-type flame retardants have attracted increasing attention due to low commercial cost and easy fabrication craft. However, traditional additive-type flame retardants usually need high addition amount to achieve a desirable effect, which causes many side-effects on the overall performance of polymer materials, such as deteriorated mechanical property and processability. At present, two-dimensional(2 D) nanomaterials have also been applied to reduce the fire hazards of polymer(nano)composites with the coupling of barrier function and catalysis as well as carbonization effect. Even though most research work mainly focus on graphene-based flame retardants, more emerging two-dimensional nanomaterials are taking away research attention, due to their complementary and unique properties, mainly including hexagonal boron nitride(h-BN), molybdenum disulfide(MoS_2), metal organic frameworks(MOF), carbon nitride(CN),titanium carbide(MXene) and black phosphorene(BP). In this review, except for graphene, the flame retardant mechanism involving different layered nanomaterials are also reviewed. Meanwhile, the functionalization method and flame retardancy effect of different layered nanomaterials are emphatically discussed for offering an effective reference to solve the fire hazards of polymer materials. Moreover, this work objectively evaluates the practical significance of polymer/layered nanomaterials composites for industrial application. 相似文献
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Jingbo Chang Guihua Zhou Erik R. Christensen Robert Heideman Junhong Chen 《Analytical and bioanalytical chemistry》2014,406(16):3957-3975
Graphene (G) is attracting significant attention because of its unique physical and electronic properties. The production of graphene through the reduction of graphene oxide (GO) is a low-cost method. The reduction of GO can further lead to electrically conductive reduced GO. These graphene-based nanomaterials are attractive for high-performance water sensors due to their unique properties, such as high specific surface areas, high electron mobilities, and exceptionally low electronic noise. Because of potential risks to the environment and human health arising from heavy-metal pollution in water, G-/GO-based water sensors are being developed for rapid and sensitive detection of heavy-metal ions. In this review, a general introduction to graphene and GO properties, as well as their syntheses, is provided. Recent advances in optical, electrochemical, and electrical detection of heavy-metal ions using graphene or GO are then highlighted. Finally, challenges facing G/GO-based water sensor development and outlook for future research are discussed. 相似文献
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A. Seeboth A. Klukowska R. Ruhmann D. Loetzsch 《高分子科学》2007,(2):123-135
Thermochromic polymers will play an extremely important role in the next future. The physical background of theimochromism and the state of development of thermochromic polymers based on light absorption effects are reported. In detail, the interactions between the polymer matrix and the thermochromic composite- composed of leuco or indicator dyes -are discussed on a molecular level. Thermochromic hydrogels with extremely high transparency, an outstanding switching behavior from colorless to colored or between different colors is presented. Preparation of thermosetting and thermoplastic polymers, including the resulting optical, and, for the first time, the mechanical properties are discussed in relation to matrix tuned high-resistant microcapsules. 相似文献
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Ren‐Gen Xiong Si‐Qi Lu Zhi‐Xu Zhang Hao Cheng Peng‐Fei Li Wei‐Qiang Liao 《Angewandte Chemie (International ed. in English)》2020,59(24):9574-9578
Switchable materials play an invaluable role in signal processing and encryption of smart devices. The development of multifunctional materials that exhibit switching characteristics in multiple physical channels has attracted widespread attention. Now, two chiral thermochromic ferroelastic crystals (S‐CTA)2CuCl4 and (R‐CTA)2CuCl4 (CTA=3‐chloro‐2‐hydroxypropyltrimethylammonium) have been prepared with switchable properties in dielectricity, conductivity, second harmonic generation (SHG), piezoelectricity, ferroelasticity, chiral, and thermochromic properties. Compared with traditional phase‐transition materials with switching features, thermochromism brings additional spectral encryption possibilities for future information processing. To the best of our knowledge, this is the first chiral thermochromic ferroelastic that exhibits switching properties in seven physical channels. This work is expected to promote further exploration of multifunctional molecular switchable materials. 相似文献
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Hybrid aerosol assisted and atmospheric pressure chemical vapour deposition methodology has been utilised to produce nanocomposite thin films of gold nanoparticles and vanadium dioxide from vanadyl acetylacetonate and auric acid. The addition of tetraoctyl ammonium bromide (TOAB) to the precursor solution gave control of the size and distribution of gold nanoparticles in the vanadium oxide matrix. These reactions led to vanadium dioxide films with reduced crystallite sizes and enhanced thermochromic properties. The films were analysed by X-ray diffraction, scanning electron microscopy and X-ray photoelectron spectroscopy. Their optical and thermochromic behaviour was also determined. This hybrid method shows great potential for the production of nanocomposite thin films with good physical properties. 相似文献