Liberating Active Metal from Reducible Oxide Encapsulation for Superior Hydrogenation Catalysis

The strong metal–support interaction (SMSI) is of significant importance to heterogeneous catalysis. The electronic modification and encapsulation of active metals by reducible supports are the intrinsic properties of the SMSI, where the latter would decrease or even cease the catalytic activity of transition metals. Here, we demonstrate for the first time that alkalis are the functional additives that can effectively manipulate the SMSI for better hydrogenation catalysis. Specifically, both thermodynamic analyses and experimental results show that the addition of alkalis to Ru/TiO2 catalyst could form titanate top layer which effectively hampers the migration of TiO2-x to the surface of Ru nanoparticle. In the meantime, a substantially enhanced reduction of support is achieved leading to an even stronger electron donation from the support to Ru. The alkali-modified Ru/TiO2 exhibits superior low-temperature catalytic activities in the hydrogenation of aromatics, which is ca. an order of magnitude higher t...