共查询到18条相似文献,搜索用时 109 毫秒
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综述了负载单中心催化剂用的镁铝载体的研究情况。主要介绍了镁铝载体的制备方法、组成、用途及特点。介绍了镁铝载体的激活能力、负载能力、能够负载的单中心催化剂种类以及负载催化剂的聚合行为,同时阐述了镁铝载体的形态特性。 相似文献
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碳基负载型催化材料凭借独特的负载结构、优异的化学稳定性和吸附特性等优势,在环境催化领域展现出广阔的应用前景,有望成为新一代绿色催化剂。研究不同维度的碳基负载金属材料与催化过一硫酸氢盐(PMS)降解污染物之间的相关性,对开发具有针对性应用的环境功能材料具有重要的指导意义。因此,本文从不同维度的碳基负载金属催化材料出发,综述了零维、一维、二维以及三维碳基负载金属催化剂活化PMS在水处理中的应用,探讨了碳基材料与其负载金属之间的相互作用、非金属元素掺杂对催化剂活性的影响以及PMS的活化机理。最后,对负载型环境催化材料未来的发展方向,如单原子催化、多反应中心体系和光电催化体系等新兴领域进行了分析和展望。 相似文献
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为研究活性炭负载Ni(Ni/AC)基催化剂在甲烷二氧化碳重整反应中的阈值效应,采用N2吸附(BET)和X射线衍射(XRD)测试技术对活性炭负载Ni(Ni/AC)基催化剂进行分析,分别探讨了浸渍溶剂和负载量对催化剂表面结构、Ni分散状态和分散阈值的影响。结果表明,采用丙酮作为溶剂制备的催化剂比纯水在活性炭载体表面更有利镍的分散,提高了活性组分有效面积,并具有更高的分散阈值。对比密置单层排列模型计算值认为Ni在AC表面呈非密置单层或亚单层分散。Ni/AC催化重整甲烷二氧化碳实验结果显示,丙酮作为浸渍溶剂比纯水制备的催化剂表现出更好的催化活性,负载型Ni/AC催化剂在甲烷二氧化碳重整反应中存在显著的阈值效应。 相似文献
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Bertrand Heurtefeu Cécile Bouilhac Éric Cloutet Daniel Taton Alain Deffieux Henri Cramail 《Progress in Polymer Science》2011,36(1):89-126
The discovery of metallocenes and post-metallocenes has revived olefin polymer chemistry as these single-site catalysts enable the production of (co)polyolefins with tunable molecular structures, stereochemistries and molecular weight distributions. To be used in industry, however, such catalysts have to be manipulated under conditions already common to existing polyolefin production processes. This means, in particular, that their heterogenization is required to produce beads of polyolefins and prevent reactor fouling, and this in turn leads to the use of supports for these catalysts. The large majority of supports currently used in industry are inorganic-based, with silica being the most important. Organic supports are also of interest as they are expected to be more versatile and less expensive. This review presents a detailed survey of the different routes to immobilizing single-site catalysts on organic supports. The various methods as well as the different types of supports are described. The influence of the organic support on the catalytic activity and main features of the thus formed polyolefin viz. molecular weight, dispersity and morphology, are also considered. 相似文献
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Group 4 bis(phenoxyimine) and related complexes are highly active olefin polymerization catalysts of the post-metallocene family. When activated with methylalumoxane, titanium complexes bearing o-fluoroaryl substituents can conduct living polymerization of ethylene and propylene. In spite of more than 10-year history of such catalysts, the origin of living behavior of such catalysts remains open to questions. This work presents the state of the art of the discussion on the living nature of single-site post-metallocene titanium based catalysts bearing o-fluoroaryl substituents. Recent experimental and theoretical results are discussed. 相似文献
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由RMgCl制备了烯烃聚合载体催化剂。SiCl_4作为氯化试剂制备的载体催化剂的活性较高。在载钛过程中,以氯苯为溶剂制备的催化剂性能最好。用这种方法制得的复合载体催化剂具有良好的共聚性能。 相似文献