One-Pot Synthesis of Oleylamine Coated AuAg Alloy NPs and Their Catalysis for CO Oxidation

A one-pot synthesis of monodisperse AuAg alloy nanoparticles (NPs) by simultaneous reduction of gold and silver salts in an organic solution was reported. 2 mol of AgNO 3 was dissolved in 20 mL of oleylamine and the solution was slowly heated to 100°C under nitrogen flow. A HAuCl 4 solution was injected into the hot solution and the solution was kept at 120°C for 0.5 hour before cooling to room temperature. The Au/Ag ratio was measured by energy-dispersive spectroscopy (EDX). Ag-rich NPs were synthesized by further increasing the amount of silver precursor. The study on composition dependent CO oxidation reveals that the alloy NPs with a Au/Ag ratio close to 1/1 have the highest activity. Their tunable optical and catalytic properties indicate that these alloy NPs have great potential as optical probes for bioimaging and as active catalyst for chemical reactions.