规则球形纳米银粉的制备及表征

Preparation and characterization of uniform spherical nanometer silver powder

采用液相化学还原法,以聚乙二醇和聚乙烯吡咯烷酮为保护剂,以次磷酸钠直接还原硝酸银得到银溶胶;将银溶胶经过后续离心分离和真空干燥处理后制备分散性好的规则球形纳米银粉;利用紫外-可见分光光度计考察反应温度和溶液的pH值对制备的纳米银粉粒度分布的影响,利用粒度分析仪测试纳米银粉的粒径分布,利用透射电镜观察纳米银粉的形貌,利用X射线衍射分析纳米银粉的晶体结构。研究结果表明,在温度为318 K,pH值为10时,可制备规则球形、面心立方晶系纯相的纳米银粉,粒径为15～25 nm,放置30 d后仍具有很强的稳定性。

Silver sols was synthesized from silver nitrate by chemical reduction in the liquid phase with sodium hypophosphite as the reducing agent, polyethylene glycol and polyvinyl pyrrolidone aa protecting agents. Spherical and well-dispersive nanometer silver powder was gained by silver sols after succedent centrifugal-separating and vacuum-dryness disposal. The influences of the reaction temperature and pH on the granularity distributions of nanometer silver powder were investigated by UV-Vis spectrophotometer, and greater intensity of absorption peak and more narrow granularity distributions of nanosilver powder were gained at different temperatures and pH values, and the prepared nanometer silver powder was characterized by granularity analysis instrument for the granularity distributions, transmission electron microscope for the figure and X-ray diffraction for the crystal configuration. The results show that the obtained nanometer silver powder is excellent with the uniform spherical shape and face-centered cubic （FCC） system with the temperature at 318 K and pH at 10. Its granularity distribution is narrow with 15-25 nm in diameter, and it is still stable after 30 d.