Characterization of highly dispersed cobalt sulfide catalysts by X-ray absorption fine structure and magnetic properties
Characterization of highly dispersed cobalt sulfide catalysts by X-ray absorption fine structure and magnetic properties
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DOI：
10.1016/j.apcata.2006.06.040
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发表时间：
2006-09-08
影响因子：
5.5
通讯作者：
Okamoto, Yasuaki
中科院分区：
文献类型：
--
作者：
Kadono, Takeshi;Kubota, Takeshi;Okamoto, Yasuaki
以CO(CO)(3)NO为前驱体，制备了沸石负载型硫化钴催化剂CoS/NaY和CoS/USY-H。采用浸渍法制备了一种负载sio2的硫化钴催化剂。对制备的催化剂进行了磁性能和XAFS表征。CoS/NaY中的硫化钴是顺磁性的，可以表征为Co原子之间具有反铁磁相互作用的沸石内双核物质，而CoS/ SiO2中的硫化钴95%是Co9S8, 5%是顺磁性的，只有少量铁磁物质。CoS/USY-H中硫化钴的结构取决于硫化后的处理方式。随着析出温度和时间的增加，硫化过程中初始形成的超高分散的硫化钴转变为高度分散的类co9s8颗粒，最终转变为离子交换的Co2+阳离子。测定了硫化钴催化剂对噻吩加氢脱硫的催化活性。结果表明，钴硫化物和表面羟基之间产生协同作用。(C) 2006 Elsevier B.V.版权所有
Zeolite-supported cobalt sulfide catalysts, CoS/NaY and CoS/USY-H, were prepared using CO(CO)(3)NO as a precursor. A SiO2-supported cobalt sulfide catalyst was prepared by an impregnation method for comparison. The prepared catalysts were characterized by magnetic properties and XAFS. The cobalt sulfides in CoS/NaY are paramagnetic and can be characterized as intrazeolite dinuclear species with antiferromagnetic interactions between the Co atoms, in contrast to the cobalt sulfides in COS/SiO2, in which 95% Of CO is Co9S8 and 5% is paramagnetic with a very small amount of ferromagnetic species. The structure of the cobalt sulfides in CoS/USY-H depends on the treatment after the sulfidation. Ultra-highly dispersed cobalt sulfide species initially formed during the sulfidation are transformed to highly dispersed Co9S8-like particles and eventually to ion-exchanged Co2+ cations as the evacuation temperature and duration are increased. The catalytic activity of the cobalt sulfide catalysts was measured for the hydrodesulfurization of thiophene. The results suggest a synergy generation between cobalt sulfides and surface hydroxyl groups. (C) 2006 Elsevier B.V. All rights reserved.