银纳米粒子的制备及其在光催化中的应用

Synthesis of silver nanoparticles and its applications in photocatalysis

在乙醇/水溶剂中,以AgNO3为银源、聚乙烯吡咯烷酮为稳定剂,采用溶剂热还原法合成纳米银。通过调变乙醇-水的相对比例、AgNO3浓度和反应时间等,获得了尺寸均匀的准球形、立方体、线状等不同形貌的银纳米颗粒,利用XRD、SEM、TEM和紫外-可见吸收光谱进行了表征。初步考察了球形纳米银(粒径分布30～70nm)和立方纳米银(粒径80～140nm)修饰介孔二氧化钛对甲基橙的光催化降解性能,结果表明两种纳米银粒子对TiO2的光催化均具有增效作用,且银粒径越小,对光催化活性的提高越显著。

Different morphologies of uniform silver nanoparticles have been synthesized in large quantities by reducing silver nitrate （AgNO3） with ethanol and/or water in the presence of poly（vinylpyrrolidone） （PVP）. The effects of the proportion of ethanol to water, the concentration of AgNO3 and the reaction time on the shapes and sizes of silver nanoparticles have been studied. The obtained quasi-nanospheres, nanocubes and nanowires silver particles were characterized by XRD, SEM, TEM and UV-vis adsorption spectroscopy. In addition, the photocatalytic performance of the Ag/mesoporous titania was investigated by UV-light induced photocatalytic degradation of methyl orange. The results showed that both nanospherical （with the diameter distribution about 30-70nm） and nanocubic （the diameter about 80-140nm） Ag nanoparticles were found to significantly enhance the photocatalytic activity of mesoporous TiO2, and the smaller Ag particles exhibited the higher improved photocatalytic activity than the big ones.