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Improvement of the activity and SO2 tolerance of Sb-modified Mn/PG catalysts for NH3-SCR at a low temperature
被引:39
作者:
Zhang, Xianlong
[1
,2
]
Lv, Shuangshuang
[1
]
Zhang, Xincheng
[1
]
Xiao, Kesong
[3
]
Wu, Xueping
[1
]
机构:
[1] Hefei Univ Technol, Sch Chem & Chem Engn, Hefei 230009, Peoples R China
[2] Hefei Univ Technol, Anhui Prov Key Lab Adv Catalyt Mat & React Engn, Hefei 230009, Peoples R China
[3] Hefei Univ Technol, Instrumental Anal Ctr, Hefei 230009, Peoples R China
来源:
JOURNAL OF ENVIRONMENTAL SCIENCES
|
2021年
/
101卷
基金:
中国国家自然科学基金;
关键词:
Manganese oxides;
Antimony oxides;
Low-temperature SCR;
Metal sulfates;
Sponge-like structure;
MANGANESE OXIDE CATALYSTS;
VANADIA-TITANIA CATALYSTS;
NITRIC-OXIDE;
NO REDUCTION;
SUPERIOR CATALYST;
MN/TIO2;
CATALYST;
MN-CE/TIO2;
NH3;
SCR;
AMMONIA;
D O I:
10.1016/j.jes.2020.07.027
中图分类号:
X [环境科学、安全科学];
学科分类号:
08 ;
0830 ;
摘要:
A series of MnM/palygorskite (PG) (M = La, W, Mo, Sb, Mg) catalysts was prepared by the wetness co-impregnation method for low-temperature selective catalytic reduction (SCR) of NO with NH3. Conversion efficiency followed the order Sb > Mo > La > W > Mg. A combination of various physico-chemical techniques was used to investigate the influence of Sb-modified Mn/PG catalysts. MnSb0.156/PG catalyst showed highest NO conversion at low temperatures in the presence of SO2 which reveals that addition of Sb oxides effectively enhances the SCR activity of catalysts. A SO2 step-wise study showed that MnSb0.156/PG catalyst displays higher durable resistance to SO2 than Mn/PG catalyst, where the sulfating of active phase is greatly inhibited after Sb doping. Scanning electron microscopy and X-ray diffraction results showed that Sb loading enhances the dispersion of Mn oxides on the carrier surface. According to the results of characterization analyses, it is suggested that the main reason for the deactivation of Mn/PG is the formation of manganese sulfates which cause the permanent deactivation of Mn-based catalysts. For Sb-doped Mn/PG catalyst, SOx ad-species formed were mainly combined with SbOx rather than MnOx. This preferential interaction between SbOx and SO2 effectively shields the MnOx as active species from being sulfated by SO2 resulting in the improvement of SO2 tolerance on Sb-added catalyst. Multiple information support that, owing to the addition of Sb, original formed MnOx crystallite has been completely transformed into highly dispersed amorphous phase accounting for higher SCR activity. (C) 2020 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.
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页码:1 / 15
页数:15
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