Sacrificial Anode Electrolysis in the Presence of Surfactants

One valid alternative to the electrolytic deposition of metal clusters is the direct electroreduction of metal ions in the presence of an appropriate stabilizer capable of preventing particle adhesion to the electrode surface. Such stabilizers adsorb onto the growing particles, thus preventing their deposition and producing structures that usually are stable within the reaction environment. These molecules can be chosen from different types of surfactant a good stabilizing agent should not interfere with the electroreduction of the metal ions, and neither should it passivate the electrode active surface. 

This technique is performed using a sacrificial anode experimental set-up, and is referred to as sacrificial anode electrolysis. During the process, the stabihzing effect can occur either at the anode or at the cathode. In the former case, the anode is made from the metal to be electrodispersed as nanostructures when the applied potential is sufficiently high, the anode dissolves into metal ions that subsequently are precipitated due to the presence of hydroxides or other anions [316]. 

A variety of different stabilizer chain lengths was explored and potential values applied in order to understand how the experimental conditions can affect NPs size-modulation. The shell thickness can easily be tailored by changing the length of the alkyl chains of the surfactant [322], while modulation of the Cu-NPs core-size could be achieved only within a very limited size range (diameter 10 nm) by varying the electrochemical parameters. The morphology of the electropro- 

A similar approach was followed by Chen and coworkers in 2003 [325] in the preparahon of copper nanorods. These authors used a controlled-current electrochemical method and showed how the shape and yield of the nanorods depended on the current density applied during the electrosynthesis process. 

Very recently, sacrificial anode electrolysis was employed by Singh and coworkers to prepare copper nanoparticles in the presence of deoxyribonucleic acid (DNA) as electrolyte [326]. Here, nanoparticles in the range 5-50nm were synthesized by using a combination of electrolysis and electron-beam irradiation. 

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