AgNPs–GO nano sheets for Aerobic Aqueous Oxidations of Alcohols

Graphene-based nanosheets have attracted remarkable attention in recent years since their discovery in 2004. One of the major concerns in the area of graphenebasedmaterials relates to the stabilization of the exfoliated sheets of graphene and GO [1]. The use of surfactants has been regarded as a highly appropriate, simple, and greener methodology for the exfoliation of GO compared with other proposed methodologies. The cytocompatibility of P123 has been studied for biological applications. Interestingly, the combination of surfactants and GO in catalytic processes has never been explored to date [2]. In this work, we propose the utilization of a surfactant combined with catalytically active Ag@GO (AgNPs–GO; NPs=nanoparticles) in chemical processes, illustrated by the selective aerobic oxidation of alcohols in aqueous media. In addition to the oxidative nature of GO, the use of the surfactant was found to improve the solubility of reactants (e.g. oxygen and organic compounds) in water, which improved the catalytic activity in the systems. In our investigations, the surface of GO was modified chemically with Ammonia and then GO sheets exfoliated by using of different surfactants such as P123, F127 and CTAB. After this step, Ag ions were loaded to the amine modified GO. Finally, Ag nanoparticles were generated via Ag ions reduction by NaBH4 solution. The achieved Ag@GO sheets (AgNPs–GO) were used in oxidation of alcohols. AgNPs–GO was found to aggregate during the oxidation reaction ofalcohols and, therefore, Ag nanoparticles were sandwiched between GO nanosheets. The catalytic activity was enhanced when cationic cetyl trimethylammonium bromide (CTAB) surfactant was used for exfoliation of GO sheets.