Selective hydrogenation of aromatic ring represents an essential process for the valorization of lignin in the chemical industry but achieving this process at low temperature is still a challenge. Herein, a series of Ru-based catalysts were investigated. It is found that Ru/gamma-Al2O3 with small Ru metal particle size shows the low activity in this system. A unique and strong metal-support interaction for Ru/gamma-Al2O3 indicates that the strongly bounded Ru-O-Al sites lead to the positive charge of Ru species. In contrast, Ru/alpha-Al2O3 with well-dispersed Ru nano particles supported on alpha-Al2O3 can successfully catalyze the selective hydrogenation of lignin-derived aromatic compounds at room temperature. Ru/alpha-Al2O3 has the excellent recyclability, air stability and the highest activity. The selective hydrogenation of aromatic ring for Ru/alpha-Al2O3 results from the fast dissociation of H-2 and the high adsorption energy of aromatic ring as revealed by X-ray absorption spectra, X-ray photoelectron spectroscopy and density functional theory calculations.
NSTL
Elsevier