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- Title
Metallic Ag Confined on SnO<sub>2</sub> Surface for Soot Combustion: the Influence of Ag Distribution and Dispersion on the Reactivity.
- Authors
Feng, Xiaohui; Zhang, Shijing; Wang, Fumin; Ma, Jun; Xu, Xianglan; Lai, Qiang; Xu, Junwei; Fang, Xiuzhong; Wang, Xiang
- Abstract
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 O2− and O22− 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 m2 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.
- Subjects
SOOT; CARBON-black; REACTIVE oxygen species; DISPERSION (Chemistry); COMBUSTION; TIN oxides
- Publication
ChemCatChem, 2021, Vol 13, Issue 9, p2222
- ISSN
1867-3880
- Publication type
Article
- DOI
10.1002/cctc.202100041