Freezing and Melting of Silver Nanoparticles on Silica Substrate Using a Simple Interatomic Potential for Ag–SiO2 Interaction on the Basis of ab Initio Calculations and Experimental Data

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• 作者：A. C. Ngandjong ; C. Mottet ; J. Puibasset
• 刊名：Journal of Physical Chemistry C
• 出版年：2017
• 出版时间：February 16, 2017
• 年：2017
• 卷：121
• 期：6
• 页码：3615-3622
• 全文大小：449K
• ISSN：1932-7455

文摘

We have devised a Ag–SiO₂ potential for Monte Carlo and molecular dynamics studies of systems comprising silver nanoparticles in contact with silica surfaces. The potential is determined based on density functional theory (DFT) calculations on β-cristobalite, a silica crystal, as well as theoretical and experimental data on α-quartz and amorphous silica found in literature. The interactions between Ag and silica species are fitted with the simple Lennard-Jones (12, 6) potential with parameters σ_Ag–O = 0.278 nm, σ_Ag–Si = 0.329 nm, ε_Ag–O = 0.012 eV, and ε_Ag–Si = 0.002 eV. The nature of the substrate is taken into account at a phenomenological level as an extra multiplicative factor η for the total interaction between silver and silica: for α-quartz η^quartz = 1, for hydroxylated β-cristobalite η^crist = 5.0, and for amorphous silica η^amorph = 2.5. This potential is thought to be useful to investigate the effect of the silica support on the structure and morphology of deposited silver nanoparticles. As an example, we study the melting and freezing of supported nanoparticles. This potential could also possibly be extended to other metals or support.