Tailoring Morphology of Cu–Ag Nanocrescents and Core–Shell Nanocrystals Guided by a Thermodynamic Model

Journal Article · Sun Jun 17 00:00:00 EDT 2018 · Journal of the American Chemical Society

DOI:https://doi.org/10.1021/jacs.8b04558· OSTI ID:1532329

Osowiecki, Wojciech T.  ^[1]; Ye, Xingchen ^[2]; Satish, Pratima ^[2]; Bustillo, Karen C. ^[3]; Clark, Ezra L. ^[1]; Alivisatos, A. Paul  ^[1]

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1. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Univ. of California, Berkeley, CA (United States)
2. Univ. of California, Berkeley, CA (United States)
3. Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)

The ability to predict and control the formation of bimetallic heterogeneous nanocrystals is desirable for many applications in plasmonics and catalysis. In this work, we observe the synthesis and characterization of stable, monodisperse, and solution-processed Cu-Ag bimetallic nanoparticles with specific but unusual elemental arrangements that are consistent with a recently developed thermodynamic model. Using air-free scanning transmission electron microscopy with energy-dispersive X-ray spectroscopy, the distribution of Cu and Ag positions was unambiguously identified within individual nanocrystals (NCs), leading to the discovery of a Cu-Ag nanocrescent shape. A simple yet versatile thermodynamic model was applied to illustrate how the interplay between surface and interface energies determines the particle morphology. It is found that there exists a range of surface-to-interface energy ratios under which crescent-shaped nanocrystals are the thermodynamically favored products, with the morphology tunable by adjusting the Ag content. Moreover, we show the conversion of Cu-Ag nanocrescents into Ag@Cu₂O upon mild oxidation, whereas fully core-shell Cu@Ag NCs are robust against oxidation up to 100 °C. The plasmonic and interband absorptions of Cu-Ag NCs depend on the composition and the degree of Cu oxidation, which may find application in light-driven catalysis.

• Research Organization: Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22). Materials Sciences & Engineering Division
• Grant/Contract Number: AC02-05CH11231; SC0004993
• OSTI ID: 1532329
• Journal Information: Journal of the American Chemical Society, Vol. 140, Issue 27; ISSN 0002-7863
• Publisher: American Chemical Society (ACS)
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY