A composition and size controllable approach for Au-Ag alloy nanoparticles
1 The Key Laboratory of Safety Science of Pressurized System (MOE), School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai, 200237, China
2 Department of Applied Chemistry, Faculty of Engineering, Utsunomiya University, 7-1-2 Yoto, Utsunomiya, 321-8585, Japan
Nanoscale Research Letters 2012, 7:225 doi:10.1186/1556-276X-7-225Published: 18 April 2012
A capillary micro-reaction was established for the synthesis of Au-Ag alloy nanoparticles (NPs) with a flexible and controllable composition and grain size by tuning the synthesis temperature, the residence time, or the mole ratio of Au3+:Ag+. By extending the residence time from 5 to 900 s, enhancing the temperature from 120°C to 160°C, or decreasing the mole ratio of Au3+:Ag+ from 1:1 to 1:20, the composition of samples was changed continuously from Au-rich to Ag-rich. The particles became large with the increase of the residence time; however, synthesis temperatures showed less effect on the particle size change. The particle size of the Au-Ag alloy NPs with various composition could be kept by adjusting the mole ratio of Au3+:Ag+. TEM observation displayed that the as-obtained NPs were sphere-like with the smallest average size of 4.0 nm, which is half of those obtained by the traditional flask method.