Abstract
Our work introduces a novel technique based on the magnetic response of Ce3+ and molecular oxygen adsorbed on the surface of nanoceria and ceria-based catalysts that quantifies the number and type of defects and demonstrates that this information is the missing link that finally enables predictive design of NOx catalysis in ceria-based systems. The new insights into ceria catalysis are enabled by quantifying the above for different ceria nanoparticle shapes (i.e., surface terminations) and O2 partial pressure. We used ceria nanorods, cubes, and spheres and evaluated them for catalytic reduction of NO by CO. We then demonstrated the quantitative prediction of the reactivity of nanomaterials via their magnetism in different atmospheric environments. We find that the observed enhancement of reactivity for ceria nanocubes and nanorods is not directly due to improved reactivity on those surface terminations but rather due to the increased ease of generating lattice defects in these materials. Finally, we demonstrate that the method is equally applicable to highly topical and industrially relevant ceria mixed oxides, using nanoscale alumina-supported ceria as a representative case-a most ill-defined catalyst. Because the total oxide surface is a mixture of active ceria and inactive support and ceria is not likely present as crystallographically well-defined phases, reactivity does not easily scale with surface area or a surface termination. The key parameter to design efficient NO reduction in ceria-based catalysts is knowing and controlling the surface localized excess Ce3+ ion areal density.
| Original language | English |
|---|---|
| Pages (from-to) | 30670-30678 |
| Number of pages | 9 |
| Journal | ACS Applied Materials and Interfaces |
| Volume | 9 |
| Issue number | 36 |
| DOIs | |
| Publication status | Published - Sep 13 2017 |
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Keywords
- Ce magnetic response
- Ce ↔ Ce redox transformation
- heterogeneous catalysis
- nanoceria
- oxygen vacancy defects
- shape-selectivity
ASJC Scopus subject areas
- Materials Science(all)
Cite this
Predicting NOx Catalysis by Quantifying Ce3+ from Surface and Lattice Oxygen. / Paidi, Vinod K.; Savereide, Louisa; Childers, David J.; Notestein, Justin M; Roberts, Charles A.; Van Lierop, Johan.
In: ACS Applied Materials and Interfaces, Vol. 9, No. 36, 13.09.2017, p. 30670-30678.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Predicting NOx Catalysis by Quantifying Ce3+ from Surface and Lattice Oxygen
AU - Paidi, Vinod K.
AU - Savereide, Louisa
AU - Childers, David J.
AU - Notestein, Justin M
AU - Roberts, Charles A.
AU - Van Lierop, Johan
PY - 2017/9/13
Y1 - 2017/9/13
N2 - Our work introduces a novel technique based on the magnetic response of Ce3+ and molecular oxygen adsorbed on the surface of nanoceria and ceria-based catalysts that quantifies the number and type of defects and demonstrates that this information is the missing link that finally enables predictive design of NOx catalysis in ceria-based systems. The new insights into ceria catalysis are enabled by quantifying the above for different ceria nanoparticle shapes (i.e., surface terminations) and O2 partial pressure. We used ceria nanorods, cubes, and spheres and evaluated them for catalytic reduction of NO by CO. We then demonstrated the quantitative prediction of the reactivity of nanomaterials via their magnetism in different atmospheric environments. We find that the observed enhancement of reactivity for ceria nanocubes and nanorods is not directly due to improved reactivity on those surface terminations but rather due to the increased ease of generating lattice defects in these materials. Finally, we demonstrate that the method is equally applicable to highly topical and industrially relevant ceria mixed oxides, using nanoscale alumina-supported ceria as a representative case-a most ill-defined catalyst. Because the total oxide surface is a mixture of active ceria and inactive support and ceria is not likely present as crystallographically well-defined phases, reactivity does not easily scale with surface area or a surface termination. The key parameter to design efficient NO reduction in ceria-based catalysts is knowing and controlling the surface localized excess Ce3+ ion areal density.
AB - Our work introduces a novel technique based on the magnetic response of Ce3+ and molecular oxygen adsorbed on the surface of nanoceria and ceria-based catalysts that quantifies the number and type of defects and demonstrates that this information is the missing link that finally enables predictive design of NOx catalysis in ceria-based systems. The new insights into ceria catalysis are enabled by quantifying the above for different ceria nanoparticle shapes (i.e., surface terminations) and O2 partial pressure. We used ceria nanorods, cubes, and spheres and evaluated them for catalytic reduction of NO by CO. We then demonstrated the quantitative prediction of the reactivity of nanomaterials via their magnetism in different atmospheric environments. We find that the observed enhancement of reactivity for ceria nanocubes and nanorods is not directly due to improved reactivity on those surface terminations but rather due to the increased ease of generating lattice defects in these materials. Finally, we demonstrate that the method is equally applicable to highly topical and industrially relevant ceria mixed oxides, using nanoscale alumina-supported ceria as a representative case-a most ill-defined catalyst. Because the total oxide surface is a mixture of active ceria and inactive support and ceria is not likely present as crystallographically well-defined phases, reactivity does not easily scale with surface area or a surface termination. The key parameter to design efficient NO reduction in ceria-based catalysts is knowing and controlling the surface localized excess Ce3+ ion areal density.
KW - Ce magnetic response
KW - Ce ↔ Ce redox transformation
KW - heterogeneous catalysis
KW - nanoceria
KW - oxygen vacancy defects
KW - shape-selectivity
UR - http://www.scopus.com/inward/record.url?scp=85029452710&partnerID=8YFLogxK
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U2 - 10.1021/acsami.7b08719
DO - 10.1021/acsami.7b08719
M3 - Article
VL - 9
SP - 30670
EP - 30678
JO - ACS applied materials & interfaces
JF - ACS applied materials & interfaces
SN - 1944-8244
IS - 36
ER -