Designing a Ru/TiO2 Catalyst with Ru Flat Island for Hydrogenation of Aromatic Compounds

Abstract

Hydrogenation of aromatic molecules is a crucial industrial process that has been extensively employed in the synthesis of fundamental chemicals. In this work, the hydrogenation of bisphenol A (BPA) was studied over a kind of Ru/TiO₂ catalyst. The catalytic activity of Ru/TiO₂ was adjusted via manipulation of the metal–support interaction (MSI) by thermal treatment. The Ru/TiO₂ exhibited a volcano-shaped dependence on calcination temperature, with the highest activity presented at 300 °C for the hydrogenation of BPA at mild conditions, produced 4,4′-isopropylidenedicyclohexanol (HBPA) with a yield of 99% at 80 °C, 4 MPa H₂. The MSI could be adjusted by varying the calcination temperature, and flat Ru islands were formed at elevated temperatures, which facilitate the adsorption of the benzene ring of BPA. However, small-sized and electron-deficient Ru species prefer to adsorb H₂. The Ru/TiO₂-300 catalyst contains an appropriate composition of Ru nanoparticles and Ru flat islands, effectively balancing the competitive adsorption of H₂ and BPA molecules, and thus exhibits high catalytic performance. Moreover, the Ru/TiO₂-300 catalyst is highly efficient for a variety of aromatic compounds, producing the desired products selectively under mild conditions. Furthermore, it presented high stability without any loss in activity after 10 recycles. This work developed an efficient catalyst for the hydrogenation of aromatic compounds, and the insights into the catalytic mechanism will provide useful information to researchers in wide fields.