Structures, Thermal Stability, and Chemical Activity of Crown-Jewel-Structured Pd–Pt Nanoalloys

Abstract

In this work, the equilibrium structures, thermal stability, and chemical activity of crown-jewel (CJ)-structured Pd–Pt nanoalloys with highly symmetric cuboctaheral (Cubo), decahedral (Dec), and icosahedral (Ico) structures are studied by using molecular simulation based on the Gupta empirical potential and density functional theory (DFT) calculations. It is found that both the melting temperature and stability of CJ-structured Pd–Pt nanoalloys with the same size follow the order of Ico > Dec > Cubo, which agrees with the rule that the more stable the cluster, the higher the melting point. In addition, the melting temperature of CJ-structured Pd–Pt nanoalloys with the same morphology is of the same linear behavior with the inverse diameter of the clusters, which is consistent with the Pawlow’s law. The adsorption properties of O on these Pd–Pt nanoalloys are studied to model the chemical activity of these nanoalloys. For the CJ-structured Pd12Pt43, the adsorption strength of O follows the order of Dec < Cubo < Ico, and the adsorption strength per O atom decreases slightly with increasing coverage of the O atom. In addition, the adsorption strength of O on the CJ-structured Pd12Pt43 is stronger than that on the CJ-structured Pd12Pt135. Our results show that the structures, thermal stability, and chemical activity of CJ-structured Pd–Pt nanoalloys are size- and morphology-dependent, which would shed new light on the design of CJ-structured nanoalloys as catalysts.

Au@Void@Ag Yolk–Shell Nanoclusters Visited by Molecular Dynamics Simulation: The Effects of Structural Factors on Thermodynamic Stability

“…According to this figure, the first-order phase transition can be identified. It can be observed that the temperature corresponding to the maximum peak value in the heat capacity is in good agreement with a simple jump of the caloric curve. , It can be observed from Figure that for all of the simulated nanoclusters configurational energies and heat capacities are decreased from 200 to 350 K, which indicates structural transformations and instability of yolk–shell structures at higher temperatures. Also, this instability of the yolk–shell regime can be observed from Figure S1 of the Supporting Information, which indicates the volume of void space as a function of temperature, and its results are in good agreement with the mentioned discussion.…”

“…It can be observed that the temperature corresponding to the maximum peak value in the heat capacity is in good agreement with a simple jump of the caloric curve. 92,93 It can be observed from Figure 2 that for all of the simulated Figure 1. Snapshots of the atomic arrangement of Au@void@Ag YSNs with variable shells and variable cores including (a) Au13@ void@Ag92, (b) Au13@void@Ag162, (c) Au13@void@Ag252, (d) Au55@void@Ag252, and (e) Au147@void@Ag252 and (f) a schematic illustration of the mentioned YSNs.…”

Surface Alloying in Silver-Cobalt through a Second Wave Solution Combustion Synthesis Technique

“…Bimetallic nanoparticles have received great attention due to their multifunctionalities, selectivity, and activity over monometallic particles, and they are increasingly being applied to various areas, including electronics, optics, catalysis, and magnetics [ 1 , 2 , 3 , 4 , 5 , 6 ]. Bimetallic nanoparticles with different structures, like crown-jewel, hollow, heterostructure, core-shell, alloys, and porous structures, have been synthesized using various techniques, such as chemical methods, hydrothermal, impregnation, sol-gel, spray pyrolysis, and precipitation methods [ 7 , 8 , 9 , 10 , 11 ]. This structural diversity is due to the atomic distribution of the individual metals in bimetals.…”

Design of High‐Performance Co‐Based Alloy Nanocatalysts for the Oxygen Reduction Reaction

“…[28] Figure 3s ,w hich agrees with the phenomenon observed in our previousw ork. [29] In short, the calculation of D andt he melting points showed that coreshell Ag 42 Co 13 exhibits the highest structural and thermals tability amongt hese Ag-Co nanoalloys with different compositions.…”

“…Therefore, the differentc harge redistributioni nt he Ag 55 , Ag 42 Co 13 ,a nd Ag 12 Co 43 clusters upon Oa dsorption can be used to explain their different adsorption strengths for O. [29]…”