Structural and Architectural Evaluation of Bimetallic Nanoparticles: A Case Study of Pt−Ru Core−Shell and Alloy Nanoparticles

Citations Over TimeTop 10% of 2009 papers

Abstract

A comprehensive structural/architectural evaluation of the PtRu (1:1) alloy and Ru@Pt core-shell nanoparticles (NPs) provides spatially resolved structural information on sub-5 nm NPs. A combination of extended X-ray absorption fine structure (EXAFS), X-ray absorption near edge structure (XANES), pair distribution function (PDF) analyses, Debye function simulations of X-ray diffraction (XRD), and field emission transmission electron microscopy/energy dispersive spectroscopy (FE-TEM/EDS) analyses provides complementary information used to construct a detailed picture of the core/shell and alloy nanostructures. The 4.4 nm PtRu (1:1) alloys are crystalline homogeneous random alloys with little twinning in a typical face-centered cubic (fcc) cell. The Pt atoms are predominantly metallic, whereas the Ru atoms are partially oxidized and are presumably located on the NP surface. The 4.0 nm Ru@Pt NPs have highly distorted hcp Ru cores that are primarily in the metallic state but show little order beyond 8 A. In contrast, the 1-2 monolayer thick Pt shells are relatively crystalline but are slightly distorted (compressed) relative to bulk fcc Pt. The homo- and heterometallic coordination numbers and bond lengths are equal to those predicted by the model cluster structure, showing that the Ru and Pt metals remain phase-separated in the core and shell components and that the interface between the core and shell is quite normal.

Related Papers

• → Comparative analysis of XANES and EXAFS for local structural characterization of disordered metal oxides(2021)28 cited
• → Investigation of Co nanoparticles with EXAFS and XANES(2004)75 cited
• → Determination of the Mo surface environment of Mo/TiO2 catalysts by EXAFS, XANES and PCA(1992)43 cited
• → Effects of Precursor Composition on the Local Structure of Cu Dispersed on Mesoporous Silica: A Detailed X-ray Absorption Spectroscopy Study(2004)37 cited
• → Investigation of the ‘‘join’’ between the near edge and extended x-ray absorption fine structure(1990)21 cited