中文摘要：

利用Au离子与树枝状纳米Ag的置换反应，以聚乙烯吡咯烷酮（PVP）为表面活性剂，制备了树枝状Ag／Au双金属纳米材料．利用扫描电子显微镜、能量散射x-射线光谱、紫外可见光光谱仪对样品的形貌、成分进行了表征分析，研究了反应温度对产物的影响．结果表明，当反应温度为180℃，反应时间为30min时，可以得到形貌保持较好的纳米枝状结构．产物的uV-Vis光谱中只观察到一个位于单金属Ag和Au之间的吸收峰，表明形成了Au／Ag合金纳米结构．随着温度升高，置换速度加快，有利于Au的生成．

英文摘要：

Au/Ag dendrite nanostructures are synthesized via a simple galvanic replacement reaction between trivalent Au ion and dendrite Ag nanostructures in the presence of polyvinyl pyrrolidone（PVP）. The morphology and composition of the samples are charac- terized by SEM,EDS and UV-vis etc. The influence of reaction temperature on the product are studied, and the results indicate that the nanodendrites can be reserved well after 30 min reaction at 180 ℃. Only an unique absorption band between monometallic Ag and Au is observed in the UV-Vis spectra, which indicates that the Au/Ag alloy nanostructures have been formed. Companying increasing reac- tion temperatures, the replacement reaction rate becomes faster, which will facilitate the formation of Au.