银纳米粒子/聚多巴胺微球的制备及催化性能

Preparation of Silver Nanoparticles/Polydopamine Nanosphere and Its Catalytic Property

利用多巴胺在碱性醇／水体系中的氧化自聚反应制备得到粒径均一的聚多巴胺纳米微球（polydopamine spheres ，PDS），并进一步利用PDS结构中儿茶酚胺的还原性，原位还原硝酸银负载银纳米粒子，建立了银纳米粒子／聚多巴胺微球（Ag nanoparticles loaded PDS ，AgNPs／PDS）的简单制备方法。利用紫外‐可见光谱、傅里叶变换红外光谱、扫描电子显微镜、X射线光电子能谱和电化学溶出伏安法对PDS及AgNPs／PDS的形貌、结构及成分进行分析。在最优条件下，粒径约为40 nm的球形AgNPs均匀固载在平均粒径约为200 nm的 PDS表面。通过紫外‐可见吸收光谱现场监测了AgNPs／PDS对硼氢化钠还原4‐硝基苯酚（4‐nitrophenol ，4‐NP）的催化作用，结果表明AgNPs／PDS极大地加速了4‐NP的还原反应。这种绿色、简单、快捷的复合材料制备方法有望为新型功能材料构建提供新途径。

Polydopamine nanosphere （PDS） with uniform particle size was prepared by oxidation and auto‐agglutination reactions of dopamine in alkaline alcohol /water system .Besides ,the simple preparation method of Ag nanoparticles loaded PDS （AgNPs/PDS ） was established through further applying reducibility of catecholamine in PDS structure and reducing silver nanoparticles loaded with silver nitrate in situ .UV‐Vis spectroscopy ,Fourier transform infrared spectroscopy ,scanning electron microscope ,X‐ray photoelectron spectroscopy and electrochemical stripping voltammetry were used to investigate the morphology ,structure and ingredients of PDS and AgNPs/PDS .Under the optimized conditions ,spherical AgNPs with the particle size of 40 nm were fixed and uniformly dispersed onto the surface of the PDS （particle size about 200 nm） .The catalytic action of AgNPs/PDS on reductions of 4‐nitrophenol （4‐NP） by sodium borohydride was monitored with UV‐Vis spectroscopy on site .The results show that AgNPs/PDS greatly accelerates reduction reaction of 4‐NP . Such green , simple and convenient composite preparation method is expected to offer a new approach to construct new functional materials .