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41.
SiO2骨架支撑MoOx催化剂用于正庚烷异构化反应 总被引:3,自引:0,他引:3
采用SEM,XRD,EDS及N2吸附-脱附方法研究了骨架型MoOx-SiO2催化剂和负载型MoOx/SiO2催化剂的物理化学结构,并在常压固定床流动反应器上考察了两种催化剂对正庚烷异构化反应的催化性能.结果表明,在MoOx-SiO2催化剂中,44.6%的SiO2即可起到很好的骨架支撑作用;MoOx晶相以足够大的空间区域聚集包裹在SiO2骨架中,形成类似MoOx催化剂的独特的中孔结构.与MoOx催化剂相比,MoOx-SiO2催化剂显著提高了机械强度,并维持了MoOx催化剂较高的活性和选择性.由于钼物种和载体之间的相互作用,负载型MoOx/SiO2催化剂表现出较低的比活性.脉冲注入H2S实验结果表明,MoOx-SiO2催化剂具有较好的抗硫性能. 相似文献
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Lijuan Shang Min Ji Tianxi Cai Weijun Shan Min He Shan Jiang 《Reaction Kinetics and Catalysis Letters》2005,87(1):101-106
Summary An AlCl3 catalyst immobilized on<span lang=EN-US style='font-family:Symbol;mso-bidi-font-family: Symbol;mso-ansi-language:EN-US'>g-Al2O3with meso- and macro-pore bimodal structure was prepared and studied in the alkylation of benzene with 1-dodecene in a suspension
bed reactor. The catalyst exhibited high activity, selectivity and stability during 1000 h running, with a 1-dodecene conversion
of more than 95%, monoalkylbenzene selectivity of 92%, and 2-phenyldodecane (2-Ph) selectivity of nearly 42%.</o:p> 相似文献
44.
The direct oxidation of ethene to acetic acid has the advantages of abundant raw materials and low cost of equipment[1],hence the research for this process has been of much interest in industry application. 相似文献
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The structural evolution and properties of poly(9,9-dihexylfluorene-alt-2,5-dialkoxybenzene) with different lengths of alkoxy side chains on phenylene have been systematically investigated by means of thermogravimetric analysis (TGA), X-ray diffraction (XRD), differential scanning calorimetry (DSC), polarizing light microscopy (PLM), atomic force microscopy (AFM), and cyclic voltammetry (CV) techniques. The polymer self-organizes into a lamellar structure consisting of both two- and one-layer packing, and the two-layer packing style is the dominant structure. In addition, the two-layer and one-layer packing structures also accompany the presence of planar stacking and/or crystalline and noncrystalline structures, thus maintaining the stability of the packing. PF6OC6 shows three ordered phases (two crystalline phases and one nematic phase) during the heating process. With further increase of the length of alkoxy side chains, only two ordered phases (one crystalline phase and one nematic phase) are observed and the polymers show a melting-recrystallization phenomenon, which is steadily inhibited as the length of the alkoxy side chains increases. The optical and electrochemical properties of the polymers do not exhibit noticeable dependence on the length of the alkoxy side chains. However, the thermal stability, the vibronic structures, and the full width at half-maximum (fwhm) in photoluminescence spectra of the films gradually decrease, and the oxidation onset potentials and the corresponding HOMO energy levels slightly increase with increasing length of alkoxy side chains on phenylene. These results indicate that the length variation of alkoxy side chains does not change the electronic structure of the polymer backbones, but remarkably affects the microphase separation between the flexible side chains and the conjugated backbones. 相似文献
47.
Hierarchical ZnCo2O4@NiCo2O4 Core–Sheath Nanowires: Bifunctionality towards High‐Performance Supercapacitors and the Oxygen‐Reduction Reaction 下载免费PDF全文
Yunpeng Huang Yue‐E. Miao Hengyi Lu Prof. Tianxi Liu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(28):10100-10108
Increasing energy demands and worsening environmental issues have stimulated intense research on alternative energy storage and conversion systems including supercapacitors and fuel cells. Here, a rationally designed hierarchical structure of ZnCo2O4@NiCo2O4 core–sheath nanowires synthesized through facile electrospinning combined with a simple co‐precipitation method is proposed. The obtained core–sheath nanostructures consisting of mesoporous ZnCo2O4 nanowires as the core and uniformly distributed ultrathin NiCo2O4 nanosheets as the sheath, exhibit excellent electrochemical activity as bifunctional materials for supercapacitor electrodes and oxygen reduction reaction (ORR) catalysts. Compared with the single component of either ZnCo2O4 nanowires or NiCo2O4 nanosheets, the hierarchical ZnCo2O4@NiCo2O4 core–sheath nanowires demonstrate higher specific capacitance of 1476 F g?1 (1 A g?1) and better rate capability of 942 F g?1 (20 A g?1), while maintaining 98.9 % capacity after 2000 cycles at 10 A g?1. Meanwhile, the ZnCo2O4@NiCo2O4 core–sheath nanowires reveal comparable catalytic activity but superior stability and methanol tolerance over Pt/C as ORR catalyst. The impressive performance may originate from the unique hierarchical core–sheath structures that greatly facilitate enhanced reactivity, and faster ion and electron transfer. 相似文献
48.
JIANG Ling ZHANG Chao WEI Junchao TJIU Wengweei PAN Jisheng CHEN Yiwang LIU Tianxi 《高等学校化学研究》2014,30(6):971-977
Surface modification of halloysite nanotube(HNT) with in situ grown Fe3O4 nanoparticles and carbonaceous layers introduced by a hydrothermal carbonization process of glucose has been achieved. Structure and morphology investigations demonstrate that iron oxide nanoparticles are uniformly anchored on the halloysite and prevent the aggregations of halloysite and carbon, forming a protective layer that stabilizes and improves the property of HNT/Fe3O4/C nanocomposite. Magnetism characterization proves the superparamagnetic behavior of HNT/Fe3O4/C hybrid at room temperature, which makes it easily separated from dye solution under an external magnetic field. Exploration of adsorption ability demonstrates that the maximum adsorption capacity of the as-prepared HNT/Fe3O4/C nanocomposite for methylene blue(MB) is about twice and 1.5 times those of HNT/Fe3O4 and HNT according to Langmuir equation, respectively. The adsorption behavior investigations indicate that HNT/Fe3O4/C hybrid has a heterogeneous structure and shows a non-ideal monolayer adsorption that fits the Redlich-Peterson isotherm, and the adsorption process follows a pseudo-second-order kinetic model. Therefore, the as-prepared HNT/Fe3O4/C hybrid is a fast, separatable and superparamagnetic adsorbent with a good adsorption ability, demonstrating great potential in the application of water treatment. 相似文献
49.
介孔材料MCM-41上汽油吸附深度脱硫 总被引:14,自引:0,他引:14
研究了不同硅铝比的MCM-41介孔材料作为吸附剂对模型汽油以及真实FCC汽油的脱硫性能. 结果表明,在室温和常压下,MCM-41介孔材料对模型溶液中噻吩的吸附随着吸附剂中铝含量的增加而显著提高. 吡啶吸附的红外光谱显示,噻吩吸附容量的提高与吸附材料酸性的明显增大有直接关系. 但在对FCC汽油的吸附脱硫实验中,随着MCM-41中铝含量的提高,脱硫率并未增大. 这主要是由于在FCC汽油中存在大量性质与噻吩类含硫化合物十分相近的芳烃和烯烃,竞争吸附导致MCM-41对有机硫化物的吸附能力显著降低. 相似文献
50.