Synthesis Of Silver Nanoparticles By Micro-Nano-bubbles Reduction Method

AgNPs can be widely used as catalyst materials, anti-static materials, low temperature superconducting materials, electronic pastes and so on. It also has many functions such as antibacterial, deodorant, absorb ultraviolet light. Its synthesis methods and application research caused people’s more and more interest. The most common synthesis methods of silver nanoparticles mainly include chemical reduction method, photochemical method, ultrasonic method, electrochemical method, etc. One of the chemical reduction methods is used widely which involved common reducing agents such as hydrazine hydrate, sodium borohydride, glucose, ascorbic acid and so on. But among these synthesis methods, they often introduced impurity and so it is not easy to remove impurities, or experimental conditions are rigid to some degree, or the experiment can only acted for less dose pilot with the problem of broadening.The reduction with hydrogen micro-nanobubbles for preparation of AgNPs has some unique advantages, for example in the reaction process there is no new impurities, and there are some papers to report the condition of H2reduction for preparation of AgNPs with high temperature (100℃). This thesis mainly explored the experiment conditions for hydrogen micro-nano bubbles to reduce silver nitrate by changing the conditions such as silver source concentration, stabilizer concentration, etc to find suitable synthetic conditions;Also we do some researches at room temperature, used silver nitrate (AgNO3) as silver source, used polyacrylic acid sodium (PAA-Na) as stabilizer, with hydrogen reduction for preparation of AgNPs and in the end we use seed growth of synthesis method to produce different colors of AgNPs; we have some interests on the sodium citrate synthesis of silver nanoparticles in the presence of Ar, N2micro-nano bubbles.The mian results are showen as below.(1)Through the experiments compared with various experimental conditions then we found that when we use hydrogen micro-nano bubbles, the concentration of silver nitrate is3×10-3mol/L, polyacrylic acid sodium concentration is10"3mol/L, and go through the solution with hydrogen for1or2minutes, the seeds of Ag with0.5mL, the result of synthesis for silver nanoparticles is possible. Its uv-visible spectra showed absorption peak position about400nm.(2) At the condition of room temperature, we use seed growth method by changing the concentration of silver nitrate, polyacrylic acid sodium concentration and the amount of seeds, the silver ion in the solution could be reduced to silver atom, then some silver atoms were crystallizing to silver clusters existed on Hydrogen bubbles without any other reducing agents and the colors of silver are very different. For more we cannot see its conglomeration just by our eyes and the color can last for very long time and its ultraviolet measurement found peak position basically unchanged.(3) The experimental results with micro-nano bubbles (Ar, N2) to use sodium citrate to synthesis silver nanoparticles showed that in the presence of micro-nano bubbles sodium citrate cannot easy to reduce silver nitrate at room temperature but when in presence of seeds silver nitrate can be reduced and silver nanoparticles is much better and more stable but we need more time at least20days.