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Abstract The nucleation and growth of nanoparticles are critical processes determining the size, shape, and properties of resulting nanoparticles. However, understanding the complex mechanisms guiding the formation and growth of colloidal multielement alloy nanoparticles remains incomplete due to the involvement of multiple elements with different properties. This study investigates in situ colloidal synthesis of multielement alloys using transmission electron microscopy (TEM) in a liquid cell. Two different pathways for nanoparticle formation in a solution containing Au, Pt, Ir, Cu, and Ni elements, resulting in two distinct sets of particles are observed. One set exhibits high Au and Cu content, ranging from 10 to 30 nm, while the other set is multi‐elemental, with Pt, Cu, Ir, and Ni, all less than 4 nm. The findings suggest that, besides element miscibility, metal ion characteristics, particularly reduction rates, and valence numbers, significantly impact particle composition during early formation stages. Density functional theory (DFT) simulations confirm differences in nanoparticle composition and surface properties collectively influence the unique growth behaviors in each nanoparticle set. This study illuminates mechanisms underlying the formation and growth of multielement nanoparticles by emphasizing factors responsible for chemical separation and effects of interplay between composition, surface energies, and element miscibility on final nanoparticles size and structure.
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Precision Synthesis of Bimetallic Nanoparticles via Nanofluidics in Nanopipets
Bimetallic nanoparticles often show properties superior to their single-component counterparts. However, the large parameter space, including size, structure, composition, and spatial arrangement, impedes the discovery of the best nanoparticles for a given application. High-throughput methods that can control the composition and spatial arrangement of the nanoparticles are desirable for accelerated materials discovery. Herein, we report a methodology for synthesizing bimetallic alloy nanoparticle arrays with precise control over their composition and spatial arrangement. A dual-channel nanopipet is used, and nanofluidic control in the nanopipet further enables precise tuning of the electrodeposition rate of each element, which determines the final composition of the nanoparticle. The composition control is validated by finite element simulation as well as electrochemical and elemental analyses. The scope of the particles demonstrated includes Cu–Ag, Cu–Pt, Au–Pt, Cu–Pb, and Co–Ni. We further demonstrate surface patterning using Cu–Ag alloys with precise control of the location and composition of each pixel. Additionally, combining the nanoparticle alloy synthesis method with scanning electrochemical cell microscopy (SECCM) allows for fast screening of electrocatalysts. The method is generally applicable for synthesizing metal nanoparticles that can be electrodeposited, which is important toward developing automated synthesis and screening systems for accelerated material discovery in electrocatalysis.
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- Award ID(s):
- 2240113
- PAR ID:
- 10499326
- Publisher / Repository:
- ACS
- Date Published:
- Journal Name:
- ACS Nano
- Volume:
- 17
- Issue:
- 22
- ISSN:
- 1936-0851
- Page Range / eLocation ID:
- 22499 to 22507
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1021/acsnano.3c06011
