Process for the preparation of bimetallic core/shell nanoparticles and their catalytic applications

An improved process for the preparation of bimetallic core-shell nanoparticles, the process comprising the steps of:

• a) adding a solution of reducing agent in water to an aqueous solution of gold precursor with constant stirring to afford gold nanoparticles followed by stirring for 10 to 15 minutes;
• b) adding a transition metal precursor to the solution of step (a) followed by adding a capping agent, wherein the capping agent is selected from the group consisting of cetyltrimethylammoniumbromide (CTAB), cetyltrimethylammonium chloride (CTAC), Poly(ethylene glycol)-block-poly(propylene glycol)-block-poly(ethylene glycol) (PEG-PPG-PEG), poly vinyl pyrollidone (PVP) and trisodiumcitrate and heating at a temperature in the range of 60 to 70° C.;
• and
• c) adding a mixture of hydrazine hydrate and sodium hydroxide to the solution of step (b) to afford the bimetallic core-shell nanoparticles, wherein a core of the core-shell nanoparticles is made up of the gold,
• a shell of the core-shell nanoparticles is made up of the transition metal, and
• said process is carried out in an aqueous medium.