Influence of hydrogenation on the mechanical properties of Pd nanoparticles.

Jianjun Bian,Gangfeng Wang,Liang Yang,Weike Yuan

doi:10.1039/d0ra08974e

Jianjun Bian, Gangfeng Wang + Show 2 more

Open Access

https://doi.org/10.1039/d0ra08974e

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Abstract

Atomic simulations are conducted to investigate the influence of hydrogenation on the mechanical properties of Pd nanoparticles. It is found that with an increase in the H atom content both the elastic modulus and the yield stress decrease approximately linearly. Moreover, the H atom content evidently alters the atomic deformation mechanisms in Pd nanoparticles. When the H atom content is in the range of 0–0.3, yield initiates from dislocation nucleating beneath surface steps and then a pyramid hillock is formed. Subsequently, dislocation nucleation and exhaustion at the surface will govern the plastic deformation. However, when the H atom content is in the range of 0.3–0.4, massive initial defects are introduced by hydrogenation, which partially suppress the dislocation nucleation around the surface steps, and no pyramid dislocation hillock is formed. Dislocation multiplication will dominate the subsequent plastic deformation. Moreover, as the H atom content increases to 0.4–0.5, the recoverable phase transition plays a key role in the plastic deformation. This study enriches our understanding of the impact of hydrogenation on the mechanical properties and deformation mechanisms of Pd nanoparticles.

Highlights

Metallic nanoparticles exhibit a great potential towards applications in such elds as energetic storage, antimicrobial materials, and high-performance catalysts
When the H atom content is in the range of 0–0.3, dislocation nucleation and exhaustion dominate the plastic deformation
The plastic responses are signi cantly affected by the H atom content

Summary

Introduction

Metallic nanoparticles exhibit a great potential towards applications in such elds as energetic storage, antimicrobial materials, and high-performance catalysts. Owing to the development of experimental and computational technologies, rich types of deformation features of the metallic nanoparticles have been revealed. Based on molecular dynamics (MD) simulations, it was found that gold nanoparticles have size-dependent modulus and yielding stress.[1] nanoindentation experiments have been performed on gold nanoparticles, and the results revealed that both the modulus and yielding stress of gold nanoparticles are higher than those of the bulk counterparts.[2] The yielding stress of metallic nanoparticles depends on the radius and the surface morphologies, such as the surface steps and amorphous surface layers.[3,4] Based on the in situ high resolution transmission electron microscopy (HTEM) results, it was revealed that silver nanoparticles with a radius of sub-10 nm could deform like a liquid droplet at room temperature.[5]

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