Abstract
Using density functional theory and cluster expansion-based Monte Carlo simulations, we examine the effect of Pd dispersion on the energetics and barriers for the reaction of O2 with H atoms to form H2O and H2O2 on a AuPd/Pd(1 1 1) alloy surface. Our calculations show that this hydrogenation reaction is considerably affected by the distribution of Pd and Au atoms in the surface layer. In particular, on isolated Pd monomers surrounded by less active Au atoms, the activation barrier to form H2O2 is appreciably lowered due to the suppression of O-O bond cleavage. In contrast, the reactivity to H2O on the Pd dimer is predicted to be enhanced compared to pure Pd. Using Monte Carlo simulations we also predict Pd ensemble populations in the AuPd surface layer as a function of temperature and composition. Due to the favorability of Au-Pd interactions over Pd-Pd, we find that small ensembles, particularly monomers, preferentially exist. This study highlights how theoretical investigation of bimetallic alloys, particularly the surface arrangement of atoms and the influence of ensembles on reaction energetics, can offer insight into the design of catalysts and tailoring of reaction conditions.
| Original language | English |
|---|---|
| Pages (from-to) | 138-144 |
| Number of pages | 7 |
| Journal | Catalysis Today |
| Volume | 165 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 2011 May 16 |
| Externally published | Yes |
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Keywords
- Cluster expansion method
- Density functional theory
- Ensemble effect
- Monte Carlo
- Oxygen reduction reaction
- PdAu alloy catalyst
ASJC Scopus subject areas
- Catalysis
- Chemistry(all)
Cite this
Pd ensemble effects on oxygen hydrogenation in AuPd alloys : A combined density functional theory and Monte Carlo study. / Ham, Hyung Chul; Stephens, J. Adam; Hwang, Gyeong S.; Han, Jonghee; Nam, SukWoo; Lim, Tae Hoon.
In: Catalysis Today, Vol. 165, No. 1, 16.05.2011, p. 138-144.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Pd ensemble effects on oxygen hydrogenation in AuPd alloys
T2 - A combined density functional theory and Monte Carlo study
AU - Ham, Hyung Chul
AU - Stephens, J. Adam
AU - Hwang, Gyeong S.
AU - Han, Jonghee
AU - Nam, SukWoo
AU - Lim, Tae Hoon
PY - 2011/5/16
Y1 - 2011/5/16
N2 - Using density functional theory and cluster expansion-based Monte Carlo simulations, we examine the effect of Pd dispersion on the energetics and barriers for the reaction of O2 with H atoms to form H2O and H2O2 on a AuPd/Pd(1 1 1) alloy surface. Our calculations show that this hydrogenation reaction is considerably affected by the distribution of Pd and Au atoms in the surface layer. In particular, on isolated Pd monomers surrounded by less active Au atoms, the activation barrier to form H2O2 is appreciably lowered due to the suppression of O-O bond cleavage. In contrast, the reactivity to H2O on the Pd dimer is predicted to be enhanced compared to pure Pd. Using Monte Carlo simulations we also predict Pd ensemble populations in the AuPd surface layer as a function of temperature and composition. Due to the favorability of Au-Pd interactions over Pd-Pd, we find that small ensembles, particularly monomers, preferentially exist. This study highlights how theoretical investigation of bimetallic alloys, particularly the surface arrangement of atoms and the influence of ensembles on reaction energetics, can offer insight into the design of catalysts and tailoring of reaction conditions.
AB - Using density functional theory and cluster expansion-based Monte Carlo simulations, we examine the effect of Pd dispersion on the energetics and barriers for the reaction of O2 with H atoms to form H2O and H2O2 on a AuPd/Pd(1 1 1) alloy surface. Our calculations show that this hydrogenation reaction is considerably affected by the distribution of Pd and Au atoms in the surface layer. In particular, on isolated Pd monomers surrounded by less active Au atoms, the activation barrier to form H2O2 is appreciably lowered due to the suppression of O-O bond cleavage. In contrast, the reactivity to H2O on the Pd dimer is predicted to be enhanced compared to pure Pd. Using Monte Carlo simulations we also predict Pd ensemble populations in the AuPd surface layer as a function of temperature and composition. Due to the favorability of Au-Pd interactions over Pd-Pd, we find that small ensembles, particularly monomers, preferentially exist. This study highlights how theoretical investigation of bimetallic alloys, particularly the surface arrangement of atoms and the influence of ensembles on reaction energetics, can offer insight into the design of catalysts and tailoring of reaction conditions.
KW - Cluster expansion method
KW - Density functional theory
KW - Ensemble effect
KW - Monte Carlo
KW - Oxygen reduction reaction
KW - PdAu alloy catalyst
UR - http://www.scopus.com/inward/record.url?scp=79955443525&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=79955443525&partnerID=8YFLogxK
U2 - 10.1016/j.cattod.2011.02.006
DO - 10.1016/j.cattod.2011.02.006
M3 - Article
VL - 165
SP - 138
EP - 144
JO - Catalysis Today
JF - Catalysis Today
SN - 0920-5861
IS - 1
ER -