Large-scale synthesis of silver nanowires via a solvothermal method
Silver nanostructures have been synthesized through a simple solvothermal method by reducing silver nitrate (AgNO3) with ethylene glycol (EG) and using poly(vinylpyrrolidone) (PVP) as an adsorption agent. Different concentrations of ferric chloride (FeCl3) are added into the solution. It is found that AgCl colloids formed in the initial stage greatly influence the final morphologies of the products. When a low-concentration FeCl3 solution is used, there is a mixture of silver nanoparticles and nanowires. However, when a high-concentration FeCl3 solution (100 μM) is used, large amounts of AgCl colloids appear, resulting in decreasing free Ag+ during initial formation of silver seeds and slowly releasing of Ag+ to the solution in the subsequent reaction. This leads to the formation of silver nanowires. Furthermore, an increase in the concentration of FeCl3 from 100 to 300 μM results in the synthesis of silver nanowires with larger sizes. In addition, Fe(III) is reduced to Fe(II) form which in turn reacts with and removes adsorbed atomic oxygen from the surface of silver seeds. In this case, uniform silver nanowires can be obtained.
The authors would like to thank Analytical and Testing Center, Huazhong University of Science and Technology, P.R. China, for the test of the samples.