In this study, we have developed a facile and effective wet-chemistry-based oxidative process for producing GNRs by lengthwise cutting and unraveling of CNT side walls with a very low usage of concentrated sulfuric acid. By introducing KNO3 in the starting CNT pretreatment, the yield of GNRs can reach nearly 100%. In addition, it is possible to reduce 90% usage of the concentrated H2SO4. The experimental findings presented in this study show that engineering of the inter- and intratube intercalation of CNTs by suitable intercalation molecules is a key factor to achieve not only high-yield GNR synthesis but also low usage of concentrated H2SO4.
In addition, we also present a controllable synthesis of Ag/GNR composites with two topics: (i) different functionality of Ag/MWGNRs (ii) different width of Ag/GNRs at the same oxidation degrees. These two syntheses of topics were by a two-step reaction route. First, we synthesized and functionalized GNRs by a facile carbon nanotube chemical unzipping. The functionalization of GNRs could be controlled, confirming by XPS characterizations. Second, Ag NPs can be decorated onto the GNRs surface through a wet-chemical-based redox reaction. Detailed hybrid materials characterizations including UV-Vis spectroscopy show that Ag/GNR composites were successfully synthesized in our experiment. We further systematic studied the Raman response of the Ag/GNR composites using Rhodamine 6G (R6G) as the Raman probe. The result indicates that the Ag/GNR composites show superior SERS performance with low detection concentration of 10-9 M of R6G and high enhance factor (EF) of 3.62×107.

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