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Angew Chem Int Ed Engl. 2016 Sep 26;55(40):12427-30. doi: 10.1002/anie.201605956. Epub 2016 Sep 4.

In Situ Observation of Hydrogen-Induced Surface Faceting for Palladium-Copper Nanocrystals at Atmospheric Pressure.

Author information

1
State Key Laboratory of Silicon Materials and Center of Electron Microscopy, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China.
2
State Key Laboratory of Silicon Materials and Center of Electron Microscopy, School of Materials Science and Engineering, Zhejiang University, Hangzhou, 310027, China. yongwang@zju.edu.cn.
3
ARC Centre for Electromaterials Science, School of Chemistry, Monash University, Clayton, Victoria, 3800, Australia. chenghua.sun@monash.edu.

Abstract

Nanocrystal (NC) morphology, which decides the number of active sites and catalytic efficiency, is strongly determined by the gases involved in synthesis, treatment, and reaction. Myriad investigations have been performed to understand the morphological response to the involved gases. However, most prior work is limited to low pressures, which is far beyond realistic conditions. A dynamic morphological evolution of palladium-copper (PdCu) NC within a nanoreactor is reported, with atmospheric pressure hydrogen at the atomic scale. In situ transmission electron microscopy (TEM) videos reveal that spherical PdCu particles transform into truncated cubes at high hydrogen pressure. First principles calculations demonstrate that the surface energies decline with hydrogen pressure, with a new order of γH-001 <γH-110 <γH-111 at 1 bar. A comprehensive Wulff construction based on the corrected surface energies is perfectly consistent with the experiments. The work provides a microscopic insight into NC behaviors at realistic gas pressure and is promising for the shaping of nanocatalysts by gas-assisted treatments.

KEYWORDS:

Wulff construction; metal-hydrogen interactions; palladium-copper nanoparticles; surface faceting

PMID:
27593991
DOI:
10.1002/anie.201605956

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