Biosynthesized ruthenium nanoparticles supported on carbon nanotubes as efficient catalysts for hydrogenation of benzene to cyclohexane: An eco-friendly and economical bioreduction method

Plenty of ruthenium nanoparticles showed a well-defined spherical shape and were distributed well on the carbon nanotubes, accompanied with superior and stabilized catalytic performance. •Ru nanoparticles are synthesized with Cacumen Platycladi extract.•Ru nanoparticles show a spherical shape and distribute well on the CNTs.•Ru/CNTs catalysts exhibit high activity toward benzene hydrogenation.•The plant biomass may be responsible for the superior catalytic performance. Ru/carbon nanotubes (CNTs) catalysts synthesized by an environmentally benign and economical bioreduction approach were applied to the hydrogenation of benzene to cyclohexane under mild conditions without adding any solvent. The catalysts were characterized by a variety of techniques including BET, TEM, HAADF-STEM -EDX, XRD, XPS, FTIR, TG, and DTG. The effect of various preparation parameters, such as Ru loading, preparation temperature and calcination temperature on the catalytic performance were systematically analyzed and the optimum conditions were found to be 2wt%, 60°C, and 500°C, respectively. In terms of reaction conditions, the combination of reaction temperature at 80°C under the pressure of 4MPa, and the time length of 0.5h proved to be optimum, under which the cycohexane yield of 99.97% along with the TOF value of 6983.09h−1 were achieved. Such results could match or even outweigh those reported in the literature. Furthermore, efforts were also made to probe the stability of catalysts. In a word, the merits of excellent durability, sound productivity and preferable reusability grant the catalysts a promising future in the industrial application.