Cu-Decorated Ru Catalysts Supported on Layered Double Hydroxides for Selective Benzene Hydrogenation to Cyclohexene

The selective hydrogenation of benzene to cyclohexene is of high value for the chemical industry owing to its inexpensive feedstock, atom economy, and operational simplicity. A tunable catalytic behavior towards the selective hydrogenation of benzene was obtained over Cu-decorated Ru catalysts supported on a layered double hydroxide (denoted as RuxCuy/MgAl-LDH), reaching a maximum cyclohexene yield of 44.0% over Ru1.0Cu0.5/MgAl-LDH at 150 degrees C and 5.0 MPa without employment of any additives. CO-TPD (TPD=temperature-pro-grammed desorption) and in situ CO-FTIR techniques demonstrated that Cu atoms preferentially deposit on the surface of low-coordinated Ru atoms in RuxCuy/MgAl-LDH catalysts, resulting in a low adsorption energy of cyclohexene on the modified sites as revealed by DFT calculations. This work not only gives an understanding of the correlation between the surface exposure of Ru active sites and the resulting selectivity, but also provides a green and additive-free catalytic process for the selective hydrogenation of benzene.