Research On The Diameter And Shape Control Of Silver Nano-particle

Because of nano-material's unique quantum size effects, small size effects, surface-interface effects and macro-quantum tunnel effects that led to the change on optics and calorifics, silver nano-particle is used in electron industry, catalyzer industry, medicine and other industry, jet achieved a widely application foreground.The research about silver nano-particle is still in developing now. Liquid phase reduction method which makes the reagents ration exactly, technical condition easy to achieve, the effect factor easy to control and the particles grow completely, is used a lot by the researchers. And with lower requirement of equipments and higher production effects, it is convenient for industry production in large scale, with a good industry application foreground.In this paper liquid phase reduction method is performed, by using silver-ammonia as the raw material,l-ascorbic acid as the reducing agent and p-dihydroxybenzene as the surface protecting reagent, with simple and efficient experimental system that is designed and made by myself. And nicely dispersed and fine crystallinity silver nano-particle is produced. The effects on silver nano-particle's average diameter of reagents'concentration, molar ratio of reducing agent to silver-ammonia, surface protecting reagent dosage, reacting temperature and time, drying temperature and time were studied through single factor experiments.The research results of silver nano-particle's average diameter shows that:the silver-ammonia solution concentration, the reducing agent concentration, the mole ratio of 1-ascorbic to silver-ammonia, p-dihydroxybenzene dosage is, the reacting temperature and time, and the drying temperature all have significant effects on the average diameter. With the the silver-ammonia solution concentration goes up, the average diameter rises; the average diameter goes first up then down with the reducing agent's concentration goes up; when the mole ratio of 1-ascorbic to silver-ammonia rises, the average diameter rises; the reacting time has huge effect on the average diameter; the average diameter rises with the temperature rising; the average diameter drops with the drying temperature rises, but the drying time has little effect on the average diameter. The minimum average diameter of silver nano-particals produced is 13nm by fine control.Based on the results of the experiments, the best technical conditions for silver nano-particle are selected. The research results of silver nano-particle's shape shows that under this circumstance achieved sphere silver nano-particle:the silver-ammonia solution concentration is 0.30mol/L, the reducing agent concentration is 0.45mol/L, the mole ratio of 1-ascorbic to silver-ammonia is 3:1, p-dihydroxybenzene dosage is 10%, the reacting temperature is 20℃, the reacting time is 30 minutes, the drying temperature is 100℃, the drying time is 4 hours. Under this circumstance achieved polyhedral silver nano-particle: the silver-ammonia solution concentration is 0.30mol/L, the reducing agent concentration is 0.45mol/L, the mole ratio of 1-ascorbic to silver-ammonia is 3:1, the reacting temperature is 20℃, the reating time is 30 minutes, the drying temperature is 100℃, the drying time is 4 hours. silver nano-particle:the silver-ammonia solution concentration is 0.30mol/L, the reducing agent concentration is 0.45mol/L, the mole ratio of 1-ascorbic to silver-ammonia is 3:1, p-dihydroxybenzene dosage is 10%, the reacting temperature is 20℃, the reacting time is 30 minutes, the drying temperature is 100℃, the drying time is 4 hours. Under this circumstance achieved branch silver nano-particle:the silver-ammonia solution concentration is 0.30mol/L, the reducing agent concentration is 0.45mol/L, the mole ratio of 1-ascorbic to silver-ammonia is 3:1, p-dihydroxybenzene dosage is 5%, the reacting temperature is 20℃, the reacting time is 60 minutes, the drying temperature is 100℃, the drying time is 4 hours.In the end of this paper, growth mechanism, crystallization and growth processes is researched simpy, and the effects that the surface protecting reagent performed on the shape of silver nano-particles during the crystal processing. The XRD curve shows that the silver nano-particle is face-centered cubic structure elemental silver with fine crystallinity.