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首页> 外文期刊>The journal of physical chemistry, B. Condensed matter, materials, surfaces, interfaces & biophysical >An X-ray Absorption Fine Structure Study of the Sulfidation Behavior of CoNaY Prepared by Ion Exchange: The Influence of Physisorbed Water and cobalt Loading
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An X-ray Absorption Fine Structure Study of the Sulfidation Behavior of CoNaY Prepared by Ion Exchange: The Influence of Physisorbed Water and cobalt Loading

机译：离子交换制备CoNaY硫化行为的X射线吸收精细结构研究：物理吸附水和钴负载量的影响

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摘要

The influence of physisorbed water on the sulfidation of a 4 wt % cobalt containing ion exchanged CoNaY catalyst is studied by X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) and high resolution electron microscopy (HREM). Upon dehydrating ion exchanged CoNaY, the Co~(2+) ions migrate into the zeolite cation positions. This migration has a large influence on the catalyst sulfidation behavior. In the presence of physisorbed water sulfidation results in the formation of large Co_9S_8 particles at the outer surface of the zeolite. On the contrary, formation of highly dispersed "Co-sulfide" species inside the zeolite cavities is observed when the physisorbed water is removed prior to sulfidation. The above findings confirm those obtained by Mossbauer emission spectroscopy (EMS) and thiophene HDS activity measurements reported earlier (de Bont, P. W.; Vissenberg, M. J.; Boellaard, E.; van Santen, R. A.; de Beer, V. H. J.; van der Kraan, A. M. Bull. Soc. Chim. Belg. 1995, 104, 205). The dispersion of the Co-sulfide species formed after sulfidation at 73 K is not affected by varying the amount of cobalt (2, 4, and 8 wt %) in the dehydrated NaY zeolite as shown by the EXAFS and MES experiments.
机译：通过近边缘结构的X射线吸收（XANES）和扩展X射线吸收的精细结构（EXAFS）和高分辨率电子显微镜（HREM）研究了物理吸附水对4 wt％含钴离子交换CoNaY催化剂硫化的影响）。离子交换的CoNaY脱水后，Co〜（2+）离子迁移到沸石阳离子位置。这种迁移对催化剂的硫化行为有很大的影响。在存在物理吸附的水的情况下，硫化会导致在沸石外表面形成大的Co_9S_8颗粒。相反，当在硫化之前除去物理吸附的水时，观察到在沸石腔内形成高度分散的“共硫化物”物质。以上发现证实了通过较早报道的Mossbauer发射光谱（EMS）和噻吩HDS活性测量获得的结果（de Bont，PW; Vissenberg，MJ; Boellaard，E .; van Santen，RA; de Beer，VHJ; van der Kraan，AM Bull。Soc。Chim。Belg。1995，104，205）。如EXAFS和MES实验所示，通过改变脱水NaY沸石中钴的含量（2、4和8 wt％），不会影响在73 K硫化后形成的Co硫化物的分散度。

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