Metallic Ag Confined on SnO2 Surface for Soot Combustion: the Influence of Ag Distribution and Dispersion on the Reactivity

被引：10

作者：

Feng, Xiaohui ^{[1
]}

Zhang, Shijing ^{[1
]}

Wang, Fumin ^{[1
]}

Ma, Jun ^{[1
]}

Xu, Xianglan ^{[1
]}

Lai, Qiang ^{[1
]}

Xu, Junwei ^{[1
]}

Fang, Xiuzhong ^{[1
]}

Wang, Xiang ^{[1
]}

机构：

[1] Nanchang Univ, Coll Chem, Key Lab Jiangxi Prov Environm & Energy Catalysis, Xuefu Ave, Nanchang, Jiangxi, Peoples R China

来源：

CHEMCATCHEM | 2021年 / 13卷 / 09期

基金：

中国国家自然科学基金;

关键词：

Ag catalyst; SnO2; support; Surface confinement effect; Metal distribution and dispersion; Soot combustion;

D O I：

10.1002/cctc.202100041

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

To unravel the surface confinement effect of SnO2 for Ag, and find an effective way to design practical soot combustion catalysts, an XRD extrapolation method has been adopted for the first time to analyze the distribution and dispersion of metallic Ag on SnO2 surface. Ag addition can generate more surface oxygen vacancies on SnO2, thus forming richer amount of surface O-2(-) and O-2(2-) anions. However, the amount of soot reactive oxygen sites is significantly influenced by the distribution of Ag. It is quantified that 1.86 mmol Ag/100 m(2) SnO2 surface, which is equal to 5.2 wt% loading, is a threshold value for Ag distribution. Below the threshold, Ag is nearly in amorphous state, and has strong interaction with the SnO2 support, thus producing more soot reactive surface oxygen sites. Furthermore, the redox property of SnO2 lattice oxygen is enhanced by Ag addition. Therefore, metallic Ag in nearly amorphous state plays a critical role for the reaction. Ag crystallites formed on the surface above the threshold have negative influence on the activity. The best Ag/SnO2 catalyst can be fabricated by loading the threshold amount of Ag over SnO2 surface to get the maximum quantity of amorphous Ag species.

引用

页码：2222 / 2233

页数：12

共 73 条

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