Mixed monolayer protected gold atom-oxide cluster synthesis and characterization.

Area of Science:

• Electrochemistry
• Nanomaterials Science
• Analytical Chemistry

Background:

• Small atomic gold clusters (Au(n)) are synthesized using potentiodynamic methods.
• Stabilization of gold clusters is achieved using cetyl trimethylammonium bromide (CTAB) and cysteine.
• The synthesis occurs in quiescent aqueous solutions.

Purpose of the Study:

• To investigate the potentiodynamic synthesis of small atomic gold clusters (Au(n)).
• To study gold electrodissolution and cluster formation in underpotential (UPDD) and overpotential dissolution-deposition (OPDD) regions.
• To demonstrate the application of gold clusters for cysteine sensing.

Main Methods:

• Potentiodynamic synthesis in aqueous solutions.
• Electrochemical studies including cyclic voltammetry and chronoamperometry.
• Analysis using theoretical models for adsorption and electrocrystallization.
• Cysteine sensing via fluorescence quenching and square wave stripping voltammetry.

Main Results:

• Experimental potentiodynamic I-E profiles and chronoamperometric i-t transients were obtained.
• The experimental data were fitted to established theoretical models.
• The synthesis and stability of Au(n) clusters were confirmed.
• A plausible sensing application for cysteine was demonstrated.

Conclusions:

• Potentiodynamic synthesis is effective for creating Au(n) clusters in solution.
• Understanding electrodissolution and deposition is key to cluster formation.
• Gold clusters and their films show promise for sensitive cysteine detection.