Preparation Of Ag Nanomaterial With Gallic Acid As Reducing Agent

Ag nanomaterial is an important part of noble metal nanomaterials. Due to their small size effect, surface effect, quantum dimension effect, macroscopic quantum tunneling effect and surface plasmon resonance effect which normal block materials don't have, they are the prominent candidates for applications in superconduction, electronics, antibacterial actions and catalysis. Ag nanomaterials have become a promising prospect for newly materials.There are many methods to prepare Ag nanoparticles domestic and abroad and new preparation methods are also emerginging.In these methods, the chemical reduction in liquid phase is a method which is often used in laboratory and industry because of its multiple advantages such as low cost , high efficiency, suitable for mass scale production. In this paper, by changing the reaction conditions, size-controlled, well-dispersed and stable silver nanoparticles were prepared using silver nitrate as silver source, gallic acid and its derivatives as reducing agents, different phosphates as protecting agent.The results showed that the hexagonal or triangular slice cut Ag nanoparticles are prepared and the nanoparticles can be controlled between 20 and 80 nm on the condition of certain protecting agent addition no matter on hydrothermal or general conditions; On hydrothermal condition, Ag nanospheres of well-dispersed ,about 40nm can be obtained when the reaction temperature is 120°C and the reaction time is only 10min by adjustment of various parameters; On normal bath conditions, spherical nanoparticles can be prepared and the nanoparticles is about 30nm in diameter when the reaction time was 10h; The optimum reducing agent are different under these two conditions, and the optimum reducing agent are gallic acid on hydrothermal condition and methyl gallate on normal bath conditions.Silver nanoparticles were characterized by UV-visible absorption spectroscopy, transmission electron microscopy and X-ray diffraction analysis. It demonstrated that though various morphology and nanometer size of silver particles vary considerably from different systems, the resulting nanoparticles are spherical, of face-centered structure and well-dispersed.