Facile Size-Controlled Synthesis of Silver Nanoparticles in UV-Irradiated Tungstosilicate Acid Solution

A method for size-controlled synthesis of silver nanocomplex is proposed and described. The synthesis is based on the reduction of silver nitrate (AgNO 3 ) by a UV-irradiated arginine (Arg)−tungstosilicate acid (TSA, H 4 SiW 12 O 40 ) solution. The method allows synthesis of spherical particles of diameter between several nanometers and several hundreds of nanometers by varying the molar ratio of silver nitrate to TSA, the pH of the reaction solution, and the reaction temperature. The formation of the Arg complexed with TSA ions is demonstrated. The experimental results show that Arg−TSA colloidal particles are a new kind of organic−inorganic template for the synthesis of organized assemblies of silver nanocomplex, wherein the Arg−TSA complex acts as a UV-switchable reducing agent for silver ion. The conductance of the Arg−TSA solution was measured as a function of reaction time. The nanoparticles were characterized by ultraviolet−visible spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction analysis, X-ray photoelectron spectroscopy, electron diffraction, and transmission electron microscopy and by use of a Zetasizer instrument.