Kayoung Yun, Yong-Hun Cho, Pil-Ryung Cha, Jaegab Lee, Jung Soo Oh, Jung-Hae Choi, Seung-Cheol Lee, Ho-Seok Nam
Pt-based bimetallic nanoparticles have attracted significant attention as a
promising replacement for expensive Pt nanoparticle catalysts. In the
systematic design of bimetallic nanoparticle catalysts, it is important to
understand their preferred atomic structures. However, compared with unary
systems, alloy catalysts present more structural complexity with various
compositional configurations, such as mixed-alloy, core-shell, and linked
monometallic nanoparticles. In this paper, we developed a unified empirical
potential model for various Pt-based binary alloys, such as Pd-Pt, Cu-Pt,
Au-Pt, and Ag-Pt. Within this framework, we performed a series of Monte Carlo
(MC) simulations that quantify the energetically favorable atomic arrangements
of Pt-based alloy nanoparticles: an intermetallic compound structure for the
Pd-Pt alloy, an onion-like multi-shell structure for the Cu-Pt alloy, and
core-shell structures (Au@Pt and Ag@Pt) for the Au-Pt and Ag-Pt alloys. The
equilibrium nanoparticle structures for the four alloy types were compared with
each other, and the structural features can be interpreted by the interplay of
their material properties, such as the surface energy and heat of formation.
View original:
http://arxiv.org/abs/1202.3277
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