An EXAFS study on oxidic and sulfided K-MoO3/gamma-Al2O3 catalysts

	An EXAFS study on oxidic and sulfided K-MoO3/gamma-Al2O3 catalysts
	Bian, GZ; Fu, YL; Xie YN(谢亚宁); Xie, YN
刊名	CATALYSIS LETTERS
	1996
卷号	40 期号:3-4 页码:#REF!
关键词	K-MoO3/Al2O3 catalysts oxidic and sulfided states EXAFS structure
英文摘要	By analyzing the extended X-ray absorption fine structure (EXAFS) of the Mo K-absorption edge, structural information for both oxidic and sulfided K-MoO3/gamma-Al2O3 catalysts with different potassium content was obtained. The oxidic samples show two backscatterer peaks in the radial distribution function (RDF), which correspond to the Mo-O coordinations in the nearest Mo-O shell. The nearest oxygen atoms are present with large configurational disorder. The RDF for the K/Mo = 0 sample is significantly different from that for crystalline MoO3 and ammonium heptamolybdate. The RDFs for potassium promoted samples are, in some extent, similar to that for ammonium heptamolybdate. The sample with K/Mo = 0.8 and that with K/Mo = 1.5 do not show obvious difference in their local Mo-O structures. The EXAFS results support the earlier conclusions from Raman spectroscopy studies on identical samples [7]. When the samples are sulfided, a rearrangement of the local neighbors around Mo atoms takes place, to form small MoS2-like crystallites. The MoS and Mo-Mo coordination distances on these catalysts are the same as those in crystalline MoS2, but the coordination numbers are significantly lower than in MoS2. The EXAFS results indicate that Mo species on the K/Mo = 0 catalyst mainly consist of MoS-Mo units (the basic building units of MoS2), which are highly dispersed and show a higher level of disorder than in MoS2. With the modification by the potassium promoter, Mo species are significantly aggregated and their local neighbors are more similar to those in MoS2, but the Mo species still exist in a state of high dispersion.
学科主题	Chemistry
类目[WOS]	Chemistry, Physical
收录类别	SCI
WOS记录号	WOS:A1996VE92300017
公开日期	2016-05-03
内容类型	期刊论文
源URL	[http://ir.ihep.ac.cn/handle/311005/227113]
专题	高能物理研究所_多学科研究中心
推荐引用方式 GB/T 7714	Bian, GZ,Fu, YL,Xie YN,et al. An EXAFS study on oxidic and sulfided K-MoO3/gamma-Al2O3 catalysts[J]. CATALYSIS LETTERS,1996,40(3-4):#REF!.
APA	Bian, GZ,Fu, YL,谢亚宁,&Xie, YN.(1996).An EXAFS study on oxidic and sulfided K-MoO3/gamma-Al2O3 catalysts.CATALYSIS LETTERS,40(3-4),#REF!.
MLA	Bian, GZ,et al."An EXAFS study on oxidic and sulfided K-MoO3/gamma-Al2O3 catalysts".CATALYSIS LETTERS 40.3-4(1996):#REF!.