Tunable synthesis solid or hollow Au–Ag nanostructure,assembled with GO and comparative study of their catalytic properties

实心、空心金-银纳米材料的可控合成,与氧化石墨烯的组装及其催化性质的对比研究(英文)

介绍了一种简单有效的制备银核金壳核壳纳米粒子(Ag@Au NPs)和银/金中空纳米笼(Ag/Au NCs)的合成方法.该方法分为两步:首先合成银纳米粒子(Ag NPs),然后以该银纳米粒子为种子,通过调整溶液的p H,实现上述两种纳米材料的可控合成.之后基于自组装的方法制备得到了银金核壳纳米粒子-氧化石墨烯纳米复合物(Ag@Au NPs-GO)及银/金中空纳米笼-氧化石墨烯纳米复合物(Ag/Au NCs-GO).研究发现,利用静电自组装的方法,Ag/Au NCs比Ag@Au NPs更容易组装到氧化石墨烯上.利用TEM, AFM, ζ-电位,HAADF-STEM,TGA及XRD等方法对所制备的杂化材料进行了表征.另外,研究了Ag@Au NPs, Ag/Au NCs 和Ag/Au NCs-GO 3种纳米材料在催化4-,3-或2-硝基苯酚还原为4-,3-或2-硝基苯胺方面所表现出的催化性质,对比研究发现其催化活性具有如下趋势:Ag/Au NCs-GO > Ag/Au NCs > Ag@Au NPs.实验结果表明,纳米杂化材料的组分和其提供的有效表面积都对其优异的催化活性起了重要作用.

In this work, we demonstrated a simple and efficacious two-step method for the synthesis of Ag@Au core–shell nanoparticles(Ag@Au NPs) and the Ag/Au hollow nanocages(Ag/Au NCs) with Ag nanoparticles(Ag NPs) as seeds by adjusting p H, and the preparation of hybrid Ag@Au NPs- or Ag/Au NCs-graphene oxide nanocomposites(Ag@Au NPs-GO or Ag/Au NCs-GO)based on the self-assembly. It was noticed from the electrostatic assembly experiment that the loading amount of Ag/Au NCs on GO nanosheet was more than that of Ag@Au NPs. The as-synthesized hybrid materials were characterized by transmission electron microscopy, atomic force microscopy, f-potential, high-angle annular darkfield scanning transmission electron microscopy, thermogravimetric analyzer and X-ray diffraction. Catalytic activities of Ag@Au NPs, Ag/Au NCs and Ag/Au NCs-GO nanostructures were investigated in the reduction of 4-, 3-or 2-nitrophenol to 4-, 3- or 2-aminophenol, and on the basis of comparative kinetic studies the following trend was obtained for the related catalytic activity: Ag/Au NCsGO [ Ag/Au NCs [ Ag@Au NPs. These observations were attributed to the simultaneous effects of surface area available for catalytic reaction and composition of the hybrid nanostructures.