Synthesis of polymer-protected palladium nanoparticles of contrasting electrocatalytic activity: A comparative study with respect to reflux time and reducing agents

Synthesis of stable palladium nanoparticles by the facile reduction of palladium chloride with citric acid and sodium citrate separately has been carried out in an aqueous solution of steric stabilizer polyvinyl alcohol (PVA). The resulting palladium nanoparticles have been characterized by physico-chemical, spectroscopic, microscopic, and cyclic voltametric studies. The average size of the nanoparticles has been tuned readily by changing the reducing agent and the extent of reflux for a chosen composition. After complete reduction of Pd (II) ions by citric acid at 2 h and sodium citrate at 20 min, Pd nanoparticles with average diameter of 21.2 and 5.3 nm respectively, were produced. Studies also reveal that palladium nanoparticles having same surface environment obtained by using a particular reducing agent and varying time of reflux, are capable to exhibit size-dependent electrocatalytic behavior for alkaline oxidation of methanol. But noticeable difference in electrocatalytic activity has been found for the nanoparticles obtained by changing the reducing agent. (C) 2010 Elsevier B.V. All rights reserved.