Key Laboratory of Functional Inorganic Material Chemistry, Ministry of Education of the People's Republic of China, Heilongjiang University, Harbin 150080, PR China.
J Colloid Interface Sci. 2012 Jun 1;375(1):30-4. doi: 10.1016/j.jcis.2012.02.051. Epub 2012 Mar 3.
In this paper, small-sized and highly dispersed Ag nanoparticles (NPs) supported on graphene nanosheets are fabricated via a strategy for etching a copper template with Ag(+). Firstly, big-sized Cu NPs are supported on graphene, and then the small-sized and highly dispersed Ag NPs are supported on graphene by replacement reaction, mainly making use of graphene passing electrons between Cu and Ag(+). The graphene used in the experiment is prepared by in situ self-generating template and has good dispersion, excellent crystallinity and little defects. Thus, in the process of Ag/graphene synthesis, there is no any intervention of surfactant, which ensures that SERS activity sites have not been passivated. And, the little defects of graphene benefit the excellent conductivity of graphene and ensured the replacement reaction between Cu and Ag(+). The obtained material exhibits significant high-quality and distinctive SERS activity. Especially, a serial new peak of p-aminothiophenol (PATP) is observed, this is suggested two reasons: one is "surface geometry" of the PATP on small-sized Ag NPs and another is the charge-transfer between Ag and graphene.
本文通过一种用 Ag(+) 刻蚀铜模板的策略，制备了负载在石墨烯纳米片上的小尺寸、高分散的 Ag 纳米颗粒 (NPs)。首先，大尺寸的 Cu NPs 负载在石墨烯上，然后通过置换反应在石墨烯上负载小尺寸、高分散的 Ag NPs，主要利用石墨烯在 Cu 和 Ag(+) 之间传递电子。实验中使用的石墨烯是通过原位自生成模板制备的，具有良好的分散性、优异的结晶度和很少的缺陷。因此，在 Ag/石墨烯合成过程中，没有任何表面活性剂的介入，从而确保了 SERS 活性位没有被钝化。而石墨烯的小缺陷有利于其具有优异的导电性，并保证了 Cu 和 Ag(+) 之间的置换反应。所得到的材料表现出显著的高质量和独特的 SERS 活性。特别是，观察到了一系列新的对氨基苯硫酚 (PATP) 的峰，这表明有两个原因：一是 PATP 在小尺寸 Ag NPs 上的“表面几何形状”，另一个是 Ag 和石墨烯之间的电荷转移。
