TY - JOUR
T1 - Structural Rearrangement of Au-Pd Nanoparticles under Reaction Conditions
T2 - An ab Initio Molecular Dynamics Study
AU - Xu, Cong Qiao
AU - Lee, Mal Soon
AU - Wang, Yang Gang
AU - Cantu, David C.
AU - Li, Jun
AU - Glezakou, Vassiliki Alexandra
AU - Rousseau, Roger
PY - 2017/2/28
Y1 - 2017/2/28
N2 - The structure, composition, and atomic distribution of nanoalloys under operating conditions are of significant importance for their catalytic activity. In the present work, we use ab initio molecular dynamics simulations to understand the structural behavior of Au-Pd nanoalloys supported on rutile TiO2 under different conditions. We find that the Au-Pd structure is strongly dependent on the redox properties of the support, originating from strong metal-support interactions. Under reducing conditions, Pd atoms are inclined to move toward the metal/oxide interface, as indicated by a significant increase of Pd-Ti bonds. This could be attributed to the charge localization at the interface that leads to Coulomb attractions to positively charged Pd atoms. In contrast, under oxidizing conditions, Pd atoms would rather stay inside or on the exterior of the nanoparticle. Moreover, Pd atoms on the alloy surface can be stabilized by hydrogen adsorption, forming Pd-H bonds, which are stronger than Au-H bonds. Our work offers critical insights into the structure and redox properties of Au-Pd nanoalloy catalysts under working conditions.
AB - The structure, composition, and atomic distribution of nanoalloys under operating conditions are of significant importance for their catalytic activity. In the present work, we use ab initio molecular dynamics simulations to understand the structural behavior of Au-Pd nanoalloys supported on rutile TiO2 under different conditions. We find that the Au-Pd structure is strongly dependent on the redox properties of the support, originating from strong metal-support interactions. Under reducing conditions, Pd atoms are inclined to move toward the metal/oxide interface, as indicated by a significant increase of Pd-Ti bonds. This could be attributed to the charge localization at the interface that leads to Coulomb attractions to positively charged Pd atoms. In contrast, under oxidizing conditions, Pd atoms would rather stay inside or on the exterior of the nanoparticle. Moreover, Pd atoms on the alloy surface can be stabilized by hydrogen adsorption, forming Pd-H bonds, which are stronger than Au-H bonds. Our work offers critical insights into the structure and redox properties of Au-Pd nanoalloy catalysts under working conditions.
KW - Au-Pd nanoalloy
KW - TiO
KW - ab initio molecular dynamics
KW - charge transfer
KW - redox property
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U2 - 10.1021/acsnano.6b07409
DO - 10.1021/acsnano.6b07409
M3 - Article
C2 - 28121422
AN - SCOPUS:85014288403
VL - 11
SP - 1649
EP - 1658
JO - ACS Nano
JF - ACS Nano
SN - 1936-0851
IS - 2
ER -