Surfactant Free Large-scale Synthesis of Palladium and Ag/Pd Nanoparticles at Ethanol/Water Refluxing Temperature

Abstract

Ag/Pd thick film paste is an important component for integrated circuit technology in electronics industry. The properties of thick film, such as high conductivity, smoothness, high density, toughness, etc., depend upon the composition of alloy, morphology, shape and size distribution of the particles. Large scale surfactant free synthesis of nanocrystalline palladium powder has been carried out by refluxing palladium chloride in ethanol without the use of any external reducing agents and any surfactants. Several batches of few grams of nano-Pd powder can be obtained in 2–5 hours and process can be monitored by UV-visible spectroscopy with disappearance of an absorption band at 425 nm originally present in PdCl₂. Similarly, silver-palladium co-powder can be synthesized by refluxing respective metal salts. It is believed that initially formed palladium nano-particles initiate the reduction of silver nitrate by acting as template. The overall reduction of silver nitrate is found to be dependent of Pd content. Powder X-ray diffraction analysis (XRD) and transmission electron microscopy (TEM) and scanning electron microscopy (SEM) confirmed spherical morphology with particle diameter is in the range of about < 10 nm.

Keywords:

• chemical synthesis
• metals
• nano particles
• XRD

We thank the Department of Information Technology (DIT), Govt. of India, for financial support through grant no. 20(7) 2003VCND and Director, C-MET, Pune for permission. PKK thanks Dr. CVVV Satyanarayana for helpful discussion.