Insights into the Activation Effect of H-2 Pretreatment on Ag/Al2O3 Catalyst for the Selective Oxidation of Ammonia

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	Insights into the Activation Effect of H-2 Pretreatment on Ag/Al2O3 Catalyst for the Selective Oxidation of Ammonia
	Wang, Fei ; He, Guangzhi ; Zhang, Bo ; Chen, Min ; Chen, Xueyan ; Zhang, Changbin ; He, Hong
刊名	ACS CATALYSIS
	2019-02-01
卷号	9 期号:2 页码:1437-1445
关键词	ammonia (NH3) Ag/Al2O3 H-2 pretreatment Ag anchoring acid site
ISSN号	2155-5435
英文摘要	The Ag/Al2O3 catalyst possesses high activity for selective catalytic oxidation of ammonia (NH3-SCO), and its activity could be significantly improved by H-2 pretreatment. It is generally accepted that the enhancement of Ag/Al2O3 activity after H-2 reduction is due to the promoted O-2 activation by metallic Ag species. Here, we show that the recovery of Bronsted acid sites via H-2 reduction is also an important factor. Ag/Al2O3 and H-2-pretreated Ag/Al2O3 (Ag/Al2O3 H-2) catalysts were prepared and tested for the NH3-SCO performances, and also carefully characterized. It is revealed that Ag species were anchored on the Al2O3 surface through exchange between Ag+ and H+ in AlOH groups during the preparation process, and therefore occupied the Bronsted acid sites of Al2O3. H-2 reduction could break the Ag-O bonds and thus recover the Bronsted acid sites. In situ DRIFTS results show that NH4+ species adsorbed on Bronsted acid sites is much more active for reaction with O-2 than NH3 species adsorbed on Lewis acid sites. DFT calculation results identified the different activation processes for NH4+ and NH3 species, confirming that Bronsted acid sites have markedly higher activity than the Lewis acid sites. Therefore, the recovery of Bronsted acid sites after H-2 reduction is also responsible for the improved activity of Ag/Al2O3-H-2 for NH3-SCO.
内容类型	期刊论文
源URL	[http://ir.rcees.ac.cn/handle/311016/43262]
专题	生态环境研究中心_水污染控制实验室
作者单位	1.Chinese Acad Sci, State Key Joint Lab Environm Simulat & Pollut Con, Res Ctr Ecoenvironm Sci, Beijing 100085, Peoples R China 2.Univ Chinese Acad Sci, Beijing 100049, Peoples R China 3.Chinese Acad Sci, Ctr Excellence Reg Atmospher Environm, Inst Urban Environm, Xiamen 361021, Peoples R China
推荐引用方式 GB/T 7714	Wang, Fei,He, Guangzhi,Zhang, Bo,et al. Insights into the Activation Effect of H-2 Pretreatment on Ag/Al2O3 Catalyst for the Selective Oxidation of Ammonia[J]. ACS CATALYSIS,2019,9(2):1437-1445.
APA	Wang, Fei.,He, Guangzhi.,Zhang, Bo.,Chen, Min.,Chen, Xueyan.,...&He, Hong.(2019).Insights into the Activation Effect of H-2 Pretreatment on Ag/Al2O3 Catalyst for the Selective Oxidation of Ammonia.ACS CATALYSIS,9(2),1437-1445.
MLA	Wang, Fei,et al."Insights into the Activation Effect of H-2 Pretreatment on Ag/Al2O3 Catalyst for the Selective Oxidation of Ammonia".ACS CATALYSIS 9.2(2019):1437-1445.