Related Experiment Videos
Dodecanethiol-protected copper/silver bimetallic nanoclusters and their surface properties
1Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543.
The Journal of Physical Chemistry. B
|July 21, 2006
Summary
Copper and silver bimetallic nanoclusters were synthesized. Surface analysis revealed copper enrichment due to a galvanic exchange process, influencing nanocluster properties.
Area of Science:
- Materials Science
- Nanotechnology
- Surface Chemistry
Background:
- Bimetallic nanoclusters offer unique properties compared to monometallic counterparts.
- Controlling surface composition is crucial for tuning nanocluster functionality.
- Dodecanethiol ligands are commonly used for stabilizing metal nanoclusters.
Purpose of the Study:
- To synthesize dodecanethiol-protected copper/silver bimetallic nanoclusters.
- To investigate the effect of varying copper to silver feed ratios on nanocluster formation and properties.
- To characterize the surface composition and thermal behavior of the bimetallic nanoclusters.
Main Methods:
- Liquid-phase synthesis of copper/silver bimetallic nanoclusters.
- Morphological and size analysis using Transmission Electron Microscopy (TEM) and X-ray Diffraction (XRD).
- Surface and spectroscopic characterization via X-ray Photoelectron Spectroscopy (XPS), Fourier Transform Infrared (FTIR) spectroscopy, Thermal Gravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC), and 13C Cross-Polarization Magic Angle Spinning Nuclear Magnetic Resonance (13C CPMAS NMR).
Main Results:
- Bimetallic nanoclusters with sizes ranging from 4-6 nm were successfully prepared.
- X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) analyses indicated significant surface enrichment of copper atoms.
- The extent of copper surface enrichment correlated directly with the copper feed ratio used during synthesis, suggesting a galvanic exchange process.
- Differential scanning calorimetry (DSC) revealed two distinct melting transitions in some samples, indicating varied dodecanethiol chain packing on heterogeneous surfaces.
Conclusions:
- Dodecanethiol-protected copper/silver bimetallic nanoclusters can be synthesized with controlled size.
- A galvanic exchange process during synthesis leads to copper enrichment on the nanocluster surfaces.
- The surface composition and ligand packing are influenced by the copper feed ratio, affecting thermal properties.