Nature of Ag Species on Ag/gamma-Al2O3: A Combined Experimental and Theoretical Study

CORC > 生态环境研究中心 > 中国科学院生态环境研究中心 > 大气污染控制中心

	Nature of Ag Species on Ag/gamma-Al2O3: A Combined Experimental and Theoretical Study
	Deng, Hua ; Yu, Yunbo ; Liu, Fudong ; Ma, Jinzhu ; Zhang, Yan ; He, Hong
刊名	ACS CATALYSIS
	2014
卷号	4 期号:8 页码:2776-2784
关键词	Ag/Al2O3 NOx SCR metal-support interaction XANES EXAFS DFT
ISSN号	2155-5435
中文摘要	The nature of silver species on Ag/Al2O3 catalysts with different silver loadings was studied by photoelectron spectroscopy (XPS) and X-ray absorption near-edge spectroscopy (XANES) and extended X-ray absorption fine structure spectroscopy (EXAFS) combined with theoretical calculation (DFT). On the basis of selective catalytic reduction of NOx by ethanol experiments, it was found that the optimum silver content varies from 1 wt % to 2 wt %. The supported silver species are predominated by +1 oxidation state ions attached to surface oxygen atoms (Ag-O) under low silver loading of 2 wt 96, which play a crucial role during the HC-SCR process. An Ag-Ag shell emerged dearly in analysis of EXAFS data when silver loading was increased to 2 wt 96, which was beneficial for low-temperature activity. The theoretical models for Ag-n(delta+) species (1 <= n <= 4, both ions and oxidized silver clusters) on alumina were consistent with the coordination structure analysis by EXAFS. The predominant silver ions are most likely stabilized at isolated tetrahedral Al sites (Ag-O-Al-IVb) on the gamma-Al2O3 (110) surface. However, the most reactive silver ion seems to be anchored on a tricoordinate Al-III site (Ag-O-Al-III). Density of states analysis revealed that the Ag-O-Al-III, entity might be a very active silver species in terms of the hybridization of Ag, O, and Al orbitals to promote its catalytic activity.
WOS记录号	WOS:000339983800048
公开日期	2015-03-24
内容类型	期刊论文
源URL	[http://ir.rcees.ac.cn/handle/311016/9284]
专题	生态环境研究中心_大气污染控制中心
推荐引用方式 GB/T 7714	Deng, Hua,Yu, Yunbo,Liu, Fudong,et al. Nature of Ag Species on Ag/gamma-Al2O3: A Combined Experimental and Theoretical Study[J]. ACS CATALYSIS,2014,4(8):2776-2784.
APA	Deng, Hua,Yu, Yunbo,Liu, Fudong,Ma, Jinzhu,Zhang, Yan,&He, Hong.(2014).Nature of Ag Species on Ag/gamma-Al2O3: A Combined Experimental and Theoretical Study.ACS CATALYSIS,4(8),2776-2784.
MLA	Deng, Hua,et al."Nature of Ag Species on Ag/gamma-Al2O3: A Combined Experimental and Theoretical Study".ACS CATALYSIS 4.8(2014):2776-2784.