Effects of Carbon Support Nanostructures on the Reactivity of a Ru Nanoparticle Catalyst in a Hydrogen Transfer Reaction

Carbon materials have been extensively studied for several decades as catalytic supports because of their high surface area and porous structures. However, carbon black supports, such as Ketjen black or Vulcan XC-72, have rarely been utilized for organic syntheses, though they have recently been widely studied in electrocatalysts. In this study, we examined Ketjen black with high surface area and high pore volume as a support for Ru nanoparticles (NPs) in the catalytic transfer hydrogenation (CTH) reaction. The performance of the Ru NP catalyst supported on Ketjen black was superior to that on other carbon supports. The catalysts were structurally characterized using X-ray diffraction, X-ray absorption fine structure, transmission electron microscopy, CO chemisorption, and N₂ adsorption/desorption measurements. A clear correlation was observed among the micro- and mesopore volume, the adsorption capacity of reactant, and the catalytic activity, and therefore, micro- and mesopores in Ketjen black were found to adsorb the reactant, acetophenone, and thus play a crucial role in achieving high catalytic performance in the CTH reaction.