Room temperature synthesis of polyvinyl alcohol stabilized palladium nanoparticles: Solvent effect on shape and electro-catalytic activity

Abstract

Palladium nanoparticles have been synthesized at room temperature, 25±.5°C by the reduction of K2PdCl4 using biocompatible polymer polyvinyl alcohol (PVA) as reducing and stabilizing agent in water and aqueous dimethyl formamide (DMF) media with varying composition of DMF. The effect of variation of composition of aqueous DMF on growth, morphology and size of palladium nanocrystals is explained. Different aqueous DMF mixtures furnish palladium nanoparticles of different shapes like triangular plates, cuboids, hexagon with different average edge length between (3–30 nm) indicating preferential interaction and blocking of DMF to some specific planes of nanocrystals leading to various shapes. The synthesized nanoparticles have been characterized by different spectroscopic, microscopic and electro-analytical studies like cyclic voltammetry (CV), chronopotentiometry (CP) and chronoamperometry (CA). The increase in electro-catalytic activity is found to decrease with the increased size of the embedded crystallites deposited on the support constituting the electrodes and hence on the precursor medium. The same order of the studied electrodes is found from mole normalized peak current density values (Amol−1Pd) in CV, transition time in CP and steady current density values in CA, on increasing the content of DMF in the aqueous DMF solvent system as expected. The outcomes are explained on the basis of the crystallite size, morphology of the surface, unequal development of certain planes and purity of the products as guided by the rate of nucleation and growth of the particles formed in different media.