Overturning CO(2)Hydrogenation Selectivity with High Activity viaReaction-Induced Strong Metal-Support Interactions br

Encapsulation of metal nanoparticles by support-derivedmaterials known as the classical strong metal-support interaction (SMSI)often happens upon thermal treatment of supported metal catalysts at hightemperatures (>= 500 degrees C) and consequently lowers the catalytic performancedue to blockage of metal active sites. Here, we show that this SMSI state canbe constructed in a Ru-MoO3catalyst using CO2hydrogenation reaction gasand at a low temperature of 250 degrees C, which favors the selective CO2hydrogenation to CO. During the reaction, Ru nanoparticles facilitatereduction of MoO3to generate active MoO3-xoverlayers with oxygenvacancies, which migrate onto Ru nanoparticles'surface and form theencapsulated structure, that is, Ru@MoO3-x. The formed SMSI state changes100% CH4selectivity on fresh Ru particle surfaces to above 99.0% CO selectivity with excellent activity and long-term catalyticstability. The encapsulating oxide layers can be removed via O2treatment, switching back completely to the methanation. This worksuggests that the encapsulation of metal nanocatalysts can be dynamically generated in real reactions, which helps to gain the targetproducts with high activity