A casting combined quenching strategy to prepare PdAg single atom alloys designed using the cluster expansion combined Monte Carlo method

Abstract

In this work, the surface structure of PdAg alloy is investigated by Cluster Expansion (CE) combined Monte Carlo (MC) simulations. All systems with different component proportion show an obvious component...

PdAg/Ag(111) Surface Alloys: A Highly Efficient Catalyst of Oxygen Reduction Reaction

“…Note that according to the number of Pd ensembles studied in previous MC simulations and experiments, the Pd monomers surrounded by Ag atoms at low temperatures are numerically more than the dimers and trimers. Therefore, the ORR overpotentials of Pd M @Ag(111) and Pd M @Pd 1L Ag(111) have a greater influence on the catalytic performance [ 48 ].…”

“…In the case of a surface alloy, a certain number of Ag atoms (1–3 Ag atoms) at the topmost Ag overlayer of a Pd 1L Ag(111) structure were replaced by Pd atoms. Note that, in our model ( Figure 1 C), the whole second layer was completely replaced by Pd atoms to simulate the fact that Pd is highly enriched in the second layer [ 48 ]. The pure metal surfaces (Ag(111), Pd(111), and Pt(111) in Figure 1 A) and modified Ag(111) surfaces that were replaced by Pd atoms only on the first layer ( Figure 1 B) were also investigated to compare with the Pd 1L Ag(111) structures.…”

“…According to our previous simulation and experimental results [ 48 ], using a combined casting and quenching strategy, PdAg alloy shows an obvious component segregation corresponding to the depth from the surface. A significant amount of Ag is observed on the first layer.…”

Theoretical design of platinum–sliver single atom alloy catalysts with CO adsorbate-induced surface structures

“…For example, the concentration of Pd atoms in the first layer is 2.95% and the concentration at the second layer is 45.44% with 30% Pd bulk concentration at 1200 K, while the concentration of Pt is 3.48% and 38.12%, respectively. 63…”

“…1(b)) as in our previous work. 63 Although this model was performed on a rigid lattice, the atomic relaxations were effectively incorporated in the effective cluster interactions using relaxed configurations for training. 64 The resulting database consisted of 633 structures.…”