Study of W/HZSM-5-based catalysts for dehydro-aromatization of CH4 in absence of O-2 II Action of promoters Zn and Li

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	Study of W/HZSM-5-based catalysts for dehydro-aromatization of CH4 in absence of O-2 II Action of promoters Zn and Li
	Zhang,HB ; Lin,GD ; Xiong,ZT ; Zeng,JL ; Zhang HB(张鸿斌)
刊名	http://dx.doi.org/10.1023/A:1016624912319
	2001
关键词	MO/HZSM-5 CATALYSTS METHANE DEHYDROGENATION CONVERSION BENZENE OXYGEN
英文摘要	By correlating the results of the NH3-TPD characteristic study and the catalyst activity assay of the W/HZSM-5-based catalysts, we confirmed that the intensity and concentration of the surface B-acid sites have pronounced effects on the catalyst performance for dehydroaromatization of methane (DHAM). It was found experimentally that, by addition of a proper amount of Mg2+, the strong B-acid sites at the catalyst surface could be effectively eliminated, whereas the addition of a proper amount of Zn2+ or Li+ resulted not only in eliminating most of the strong surface B-acid sites but also in generating a kind of new medium-strong acid sites, mostly B-acid sites, simultaneously. The latter could serve as the catalytically active sites for dehydro-aromatization of methane; on such medium-strong surface B-acid sites, the formation of coke would be also alleviated to a greater extent. By simultaneous addition of Mg2+ and Zn2+, optimized adjustment in surface acidity of the catalyst could be realized. On the other hand, the doping of the Zn2+ or Li+ component to the tungsten oxide matrix would facilitate inhibiting aggregation of the W-containing active species and improving dispersion of the W component at the surface of the catalyst, thus leading to a pronounced decrease in the reduction temperature for the hard-to-be-reduced W6+ species and an increase in quantity of the reducible W6+ species at the reaction temperature for DHAM, as has been evidenced by the results of a H-2-TPR study on the reducibility of the Zn2+ (or La3+, Li+, Mn2+)-promoted W/HZSM-5 system. The above two roles that Zn2+ and Li+ as promoters played both contributed to the persistence of high methane conversion and benzene selectivity, and the alleviation of coke deposition, as well as the prolongation of the catalyst lifetime.
语种	英语
内容类型	期刊论文
源URL	[http://dspace.xmu.edu.cn/handle/2288/62034]
专题	化学化工－已发表论文
推荐引用方式 GB/T 7714	Zhang,HB,Lin,GD,Xiong,ZT,et al. Study of W/HZSM-5-based catalysts for dehydro-aromatization of CH4 in absence of O-2 II Action of promoters Zn and Li[J]. http://dx.doi.org/10.1023/A:1016624912319,2001.
APA	Zhang,HB,Lin,GD,Xiong,ZT,Zeng,JL,&张鸿斌.(2001).Study of W/HZSM-5-based catalysts for dehydro-aromatization of CH4 in absence of O-2 II Action of promoters Zn and Li.http://dx.doi.org/10.1023/A:1016624912319.
MLA	Zhang,HB,et al."Study of W/HZSM-5-based catalysts for dehydro-aromatization of CH4 in absence of O-2 II Action of promoters Zn and Li".http://dx.doi.org/10.1023/A:1016624912319 (2001).