Revealing Surface Elemental Composition and Dynamic Processes Involved in Facet-Dependent Oxidation of Pt3Co Nanoparticles via in Situ Transmission Electron Microscopy

Sheng Dai(1), Yusheng Hou(2), Masatoshi Onoue(2), Shuyi Zhang(1,3), Wenpei Gao(1), Xingxu Yan(1), George W. Graham(1,3), Ruqian Wu(2), Xiaoqing Pan(1,2), 2017

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Abstract

Since catalytic performance of platinum–metal (Pt–M) nanoparticles is primarily determined by the chemical and structural configurations of the outermost atomic layers, detailed knowledge of the distribution of Pt and M surface atoms is crucial for the design of Pt–M electrocatalysts with optimum activity. Further, an understanding of how the surface composition and structure of electrocatalysts may be controlled by external means is useful for their efficient production. Here, we report our study of surface composition and the dynamics involved in facet-dependent oxidation of equilibrium-shaped Pt3Co nanoparticles in an initially disordered state via in situtransmission electron microscopy and density functional calculations. In brief, using our advanced in situ gas cell technique, evolution of the surface of the Pt3Co nanoparticles was monitored at the atomic scale during their exposure to an oxygen atmosphere at elevated temperature, and it was found that Co segregation and oxidation take place on {111} surfaces but not on {100} surfaces. Keywords: facet-dependent oxidation; gas cell; in situ TEM; Pt−Co nanoparticles; surface elemental distribution

Impact Statement

Here, the authors studied the facet-dependant oxidation of Pt3Co NPs at high temperature in 1 atm of O2. They found that certain facets will preferentially oxidize {111} and model the dynamics of this behaviour using DFT.