The solvent-free selective hydrogenation of nitrobenzene to aniline: an unexpected catalytic activity of ultrafine Pt nanoparticles deposited on carbon nanotubes

In this work, we developed a facile and efficient route to deposit ultrafine Pt particles onto multi-walled carbon nanotubes (MWNTs) with the aid of tip sonication. The loading of Pt on the MWNTs could attain the very high level of 50 wt% and the size of the Pt particles could be controllably tuned in the range 1.9–3.5 nm with narrow size distributions. The resultant nanocomposites were applied to catalyze the hydrogenation of nitrobenzene under solvent-free conditions. It was demonstrated that the Pt/MWNT catalysts showed excellent activity with a high turnover frequency (e.g., 69 900 h⁻¹) as well as superior selectivity to aniline (e.g., >99%) in this reaction.