Nonaqueous phase synthesis of copper nanoparticles

Area of Science:

• Materials Science
• Nanotechnology
• Chemistry

Background:

• Copper nanoparticles (Cu NPs) exhibit unique properties making them valuable in various applications.
• Controlling the synthesis of Cu NPs is crucial for tailoring their characteristics.
• Nonaqueous synthesis offers an alternative route for nanoparticle fabrication.

Purpose of the Study:

• To synthesize copper nanoparticles in a nonaqueous medium.
• To investigate the role of cetyltrimethylammonium bromide (CTAB) concentration on Cu NP formation and characteristics.
• To explore the catalytic role of CTAB and the reducing properties of isopropanol.

Main Methods:

• Synthesis of copper nanoparticles via a nonaqueous route using copper(II) precursor and cetyltrimethylammonium bromide (CTAB) in isopropanol.
• Characterization using UV-visible spectroscopy to identify surface plasmon bands.
• Analysis of crystal structure and phase purity using X-ray diffraction (XRD).
• Determination of particle size and morphology through transmission electron microscopy (TEM).

Main Results:

• UV-Vis spectra showed characteristic surface plasmon bands for Cu NPs at ~560 nm at CTAB:Cu2+ ratios of 1:15 and 1:30.
• A peak at ~310 nm, attributed to Cu0 oligomeric clusters, was observed at lower CTAB ratios (1:0.25 and 1:1).
• XRD confirmed the formation of Cu0 with characteristic peaks.
• TEM revealed size-controlled synthesis: higher CTAB concentration (1:30) resulted in finer particles (2-10 nm) with less dispersity, while lower CTAB (1:0.25) yielded larger, more dispersed particles (5-20 nm).

Conclusions:

• Cetyltrimethylammonium bromide acts as a catalyst in isopropanol, which serves as the reducing agent for copper nanoparticle synthesis.
• The concentration of CTAB significantly influences the size and size distribution of the synthesized copper nanoparticles.
• This nonaqueous method allows for controlled synthesis of copper nanoparticles with tunable characteristics.