Metal-acid site synergistic catalysis in Ru–ZrO2 toward selective hydrogenation of benzene to cyclohexene
Ruthenium-based catalysts are one of the most promising candidates toward selective hydrogenation of benzene. In this work, we synthesized a novel core–shell catalyst by coating porous B-doped ZrO2 on the surface of Ru/ZrO2 particles (denoted as Ru/ZrO2@ZrO2-B(x%)), in which the hydrogen dissociation occurs on the inner surface of metal Ru and the acid site of the exterior ZrO2-B(x%) serves as the adsorption site for benzene. The Ru/ZrO2@ZrO2-B(5%) sample demonstrates the optimal synergistic catalysis between metal Ru and the weak/medium-strong Lewis acid site of the ZrO2-B(5%) layer, which promotes the activated adsorption of benzene and desorption of cyclohexene. Therefore, it exhibits the best catalytic performance (benzene conversion: 53.1%; cyclohexene selectivity: 58.8%) without using any additives.