Nanostructured RuO2 on MWCNTs: Efficient catalyst for transfer hydrogenation of carbonyl compounds and aerial oxidation of alcohols

Abstract

Multiwall carbon nanotubes (MWCNTs)/ruthenium dioxide nanoparticles (RuO2NPs) composite was prepared by a straightforward ‘dry synthesis’ method. After being well characterized, the prepared composite was used as a nanocatalyst (RuO2/MWCNT) for the transfer hydrogenation of carbonyl compounds. The excellent adhesion of RuO2NPs on the anchoring sites of MWCNTs was confirmed by TEM and Raman analyses. The weight percentage (7.97wt%) and the chemical state (+4) of Ru in RuO2/MWCNT was confirmed by EDS and XPS analyses, respectively. It was found that the RuO2/MWCNT has a higher specific surface area of 189.3m2g−1. Initially the reaction conditions were optimized and then the scope of the catalytic system was extended with a wide range of carbonyl compounds. The influence of the size of RuO2NPs on the transfer hydrogenation of carbonyl compounds was also studied. The RuO2/MWCNT is highly chemoselective, heterogeneous in nature, reusable and highly stable. Owing to the high stability of the used catalyst (u-RuO2/MWCNT), it was further calcinated at high temperature to obtain RuO2 nanorods (NRs) hybrid MWCNTs. Then the hybrid material was used as a catalyst (r-RuO2/MWCNT) for the aerial oxidation of alcohols and the result was found to be good.