Abstract
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.
Original language | English |
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Pages (from-to) | 1649-1658 |
Number of pages | 10 |
Journal | ACS Nano |
Volume | 11 |
Issue number | 2 |
DOIs | |
State | Published - Feb 28 2017 |
Externally published | Yes |
Funding
The authors M.S.L., Y.G.W., D.C.C., V.A.G., and R.R. were supported by the U.S. Department of Energy (DOE), Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences, & Biosciences. All the calculations were performed at the Pacific Northwest National Laboratory (PNNL), which is operated by Battelle for the DOE. The authors C.Q.X. and J.L. were financially sponsored by NSFC (21521091) and NKBRSF (2013CB834603) of China. Computational resources were provided by the W. R. Wiley Environmental Molecular Science Laboratory (EMSL), a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and PNNL Institutional Computing (PIC) program, both located at Pacific Northwest National Laboratory.
Keywords
- Au-Pd nanoalloy
- TiO
- ab initio molecular dynamics
- charge transfer
- redox property