Alkali Metal-Promoted LaxSr2-xFeO4-delta Redox Catalysts for Chemical Looping Oxidative Dehydrogenation of Ethane

doi:10.1021/acscatal.7b03928

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	Alkali Metal-Promoted LaxSr2-xFeO4-delta Redox Catalysts for Chemical Looping Oxidative Dehydrogenation of Ethane
	Gao, Yunfei 1; Haeri, Farrah 1; He, Fang2 ; Li, Fanxing 1
	2018-03-01
发表期刊	ACS CATALYSIS
ISSN	2155-5435
卷号	8 期号:3 页码:1757-1766
通讯作者	Li, Fanxing(fli5@ncsu.edu)
摘要	Chemical looping oxidative dehydrogenation (CL-ODH) represents a redox approach to convert ethane into ethylene under an autothermal scheme. Instead of using gaseous oxygen, CL-ODH utilizes lattice oxygen in transition metal oxides, which acts as an oxygen carrier or redox catalyst, to facilitate the ODH reaction. The oxygen-deprived redox catalyst is subsequently regenerated with air and releases heat. The current study investigated alkali metal (Li, Na, and/or K)-promoted LaxSr2-x,FeO4-delta (LaSrFe) as redox catalysts for CL-ODH of ethane. While unpromoted LaSrFe exhibited poor ethylene selectivity, addition of Na or K promoter achieved up to 61% ethane conversion and 68% ethylene selectivity at 700 degrees C. The promotional effect of K on LaSrFe was characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), low-energy ion scattering spectroscopy (LEIS), transmission electron microscopy (TEM), O-2-temperature-programmed desorption (TPD), H-2-temperature-programmed reduction (TPR), and O-18(2) surface exchange. XPS and XRD showed that K incorporates into the mixed-oxide structure at low loading levels (e.g., 0.1K-LaSrFe), whereas the surface of LaSrFe was enriched with K cation at high loading levels. LEIS indicates that the outermost surface layer was covered by potassium oxide. This surface layer was characterized to be amorphous under TEM. It was further determined that the surface layer increased the resistance for O2- diffusion from the bulk and its subsequent evolution into electrophilic oxygen species on the surface. As such, nonselective oxidation of ethane is inhibited. The synergistic effect of copromoting LaSrFe with Li and K was also investigated. Li and K copromotion improved the redox catalyst performance to 86% ethylene selectivity and 60% ethane conversion while maintaining an oxygen capacity of ca. 0.65 wt %, making it a promising candidate for CL-ODH.
关键词	oxidative dehydrogenation chemical looping redox catalyst core-shell perovskite alkali promotion
DOI	10.1021/acscatal.7b03928
关键词[WOS]	METHANE PARTIAL OXIDATION ; CHLORIDE CATALYSTS ; OXIDE CATALYSTS ; LIGHT ALKANES ; OXYGEN ; POTASSIUM ; ETHYLENE ; PROPANE ; SCHEME ; KINETICS
收录类别	SCI
语种	英语
资助项目	U.S. National Science Foundation[CBET-1604605] ; Kenan Institute for Engineering, Technology, and Science at NC State University ; State of North Carolina ; National Science Foundation
WOS研究方向	Chemistry
项目资助者	U.S. National Science Foundation ; Kenan Institute for Engineering, Technology, and Science at NC State University ; State of North Carolina ; National Science Foundation
WOS类目	Chemistry, Physical
WOS记录号	WOS:000426804100018
出版者	AMER CHEMICAL SOC
引用统计	被引频次：67[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://ir.giec.ac.cn/handle/344007/23285
专题	中国科学院广州能源研究所
通讯作者	Li, Fanxing
作者单位	1.North Carolina State Univ, Dept Chem & Biomol Engn, 911 Partners Way, Raleigh, NC 27695 USA 2.Chinese Acad Sci, Guangzhou Inst Energy Convers, Guangzhou 510640, Guangdong, Peoples R China
推荐引用方式 GB/T 7714	Gao, Yunfei,Haeri, Farrah,He, Fang,et al. Alkali Metal-Promoted LaxSr2-xFeO4-delta Redox Catalysts for Chemical Looping Oxidative Dehydrogenation of Ethane[J]. ACS CATALYSIS,2018,8(3):1757-1766.
APA	Gao, Yunfei,Haeri, Farrah,He, Fang,&Li, Fanxing.(2018).Alkali Metal-Promoted LaxSr2-xFeO4-delta Redox Catalysts for Chemical Looping Oxidative Dehydrogenation of Ethane.ACS CATALYSIS,8(3),1757-1766.
MLA	Gao, Yunfei,et al."Alkali Metal-Promoted LaxSr2-xFeO4-delta Redox Catalysts for Chemical Looping Oxidative Dehydrogenation of Ethane".ACS CATALYSIS 8.3(2018):1757-1766.