American Chemical Society
jp402978q_si_001.pdf (2.2 MB)

Dry Synthesis of Easily Tunable Nano Ruthenium Supported on Graphene: Novel Nanocatalysts for Aerial Oxidation of Alcohols and Transfer Hydrogenation of Ketones

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journal contribution
posted on 2013-11-14, 00:00 authored by Mayakrishnan Gopiraman, Sundaram Ganesh Babu, Zeeshan Khatri, Wei Kai, Yoong Ahm Kim, Morinobu Endo, Ramasamy Karvembu, Ick Soo Kim
In this study, ruthenium nanoparticles (RuNPs) were successfully decorated on graphene nanosheets (GNSs) for the very first time by a dry synthesis method. The resultant material (GNS-RuNPs) was used as a nanocatalyst for the aerial oxidation of alcohols after being optimized. The scope of the catalytic system was extended with various aliphatic, aromatic, alicyclic, benzylic, allylic, amino, and heterocyclic alcohols. The 0.036 mol % (5 mg) of catalyst was enough for aerial oxidation of alcohols, the lowest amount of catalyst so far reported. The proposed nanocatalyst is highly chemoselective, heterogeneous, and reusable. The GNS-RuNPs were separated out from the reaction mixture and analyzed by transmission electron microscopy (TEM), X-ray diffraction (XRD), Raman, and scanning electron microscopy-energy dispersive spectrometry (SEM-EDS); the results revealed that the nanocatalyst is physically as well as chemically stable. Owing to the high stability of used catalyst (u-GNS-RuNPs), it was further applied in transfer hydrogenation, after suitable modifications. We obtained ruthenium oxide nanorod hybrid GNSs (u-GNS-RuO2NRs) from u-GNS-RuNPs by simple calcination. The catalytic activity of u-GNS-RuO2NRs toward the transfer hydrogenation of various aromatic, alicyclic, and heterocyclic ketones was found to be excellent.