title: Structural Rearrangement of Au-Pd Nanoparticles under Reaction Conditions: An ab Initio Molecular Dynamics Study.
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 TiO2under 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.
authors.affiliation: Department of Chemistry, Tsinghua University , Beijing 100084, China.
authors.forename: Cong-Qiao
authors.identifier: 0000-0003-4593-3288
authors.initials: CQ
authors.lastname: Xu
authors.forename: Mal-Soon
authors.identifier: 0000-0001-6851-177X
authors.initials: MS
authors.lastname: Lee
authors.forename: Yang-Gang
authors.identifier: 0000-0002-0582-0855
authors.initials: YG
authors.lastname: Wang
authors.forename: David C
authors.initials: DC
authors.lastname: Cantu
authors.affiliation: Department of Chemistry, Tsinghua University , Beijing 100084, China.
authors.forename: Jun
authors.identifier: 0000-0002-8456-3980
authors.initials: J
authors.lastname: Li
authors.forename: Vassiliki-Alexandra
authors.initials: VA
authors.lastname: Glezakou
authors.forename: Roger
authors.initials: R
authors.lastname: Rousseau
keywords: Au−Pd nanoalloy; TiO2; ab initio molecular dynamics; charge transfer; redox property