Preparation and growth mechanism study of polymer protected Au/Pd bimetallic nanoparticles by simultaneous reduction of HAuCl ₄ and PdCl ₂

We report on the preparation of polymer-protected gold-palladium bimetallic particles in colloidal form by the reduction of corresponding metal ions simultaneously. Formation of nanoparticles and their constitution were studied by x-ray diffraction (XRD), transmission electron microscopy (TEM) and optical absorption spectroscopy techniques. The average size of the particles depended strongly on the molar ratio of two metal ions in the reaction mixture. XRD study revealed that the Au/Pd colloids prepared with different molar ratios form some partially alloyed structure of those metals. A high concentration of Pd ions in the reaction mixture produces non-dispersed small bimetallic colloids. Mechanism of formation of bimetallic Au/Pd particles has been studied.