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Energy Dispersive X-ray Tomography for 3D Elemental Mapping of Individual Nanoparticles
Published on: July 5, 2016
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Segregation effects on the properties of (AuAg)₁₄₇
A L Gould1, C J Heard, A J Logsdail
1Rutherford Appleton Laboratory, Harwell Oxford Didcot, Oxon, OX11 0FA, UK. a.gould@ucl.ac.uk.
Physical Chemistry Chemical Physics : PCCP
|April 24, 2014
Summary
Chemical ordering in gold-silver (AuAg) nanoclusters significantly impacts their electronic properties for photocatalysis. Density Functional Theory (DFT) reveals core-shell structures are energetically favored, enhancing catalytic activity.
Area of Science:
- Materials Science
- Nanotechnology
- Physical Chemistry
Background:
- Gold-silver (AuAg) nanoclusters are effective co-catalysts for photocatalytic hydrogen production.
- Understanding the influence of chemical ordering on electronic properties beyond the quantum regime is crucial.
Purpose of the Study:
- To investigate the effect of chemical ordering on the electronic properties of 147-atom AuAg nanoclusters.
- To determine the most stable elemental arrangements and their impact on co-catalyst performance.
Main Methods:
- Empirical potentials and atomic-swap basin-hopping were used to optimize elemental distribution.
- Density Functional Theory (DFT) was employed for energy minimization and electronic structure analysis.
Main Results:
- Force-field calculations suggested a pseudo-onion structure with gold in sub-surface positions.
- DFT calculations revealed that Ag@Au core-shell structures are energetically favored, with gold shells facilitating electron density accumulation.
- This leads to a partial negative charge on the nanocluster, beneficial for catalysis.
Conclusions:
- Chemically ordered Ag@Au core-shell nanoclusters are promising for co-catalyzed photocatalysis.
- The electronic properties and stability are strongly dependent on the specific arrangement of gold and silver atoms.
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