Shape dependency of CO2 hydrogenation on ceria supported singly dispersed Ru catalysts

Harnessing the selectivity in catalytic hydrogenation of CO 2 is important for producing valuable chemicals. Herein, the shape dependency of the CO 2 hydrogenation on singly dispersed Ru/CeO 2 catalysts is investigated. CeO 2 of three shapes, including nanocube, nanooctahedron and nanorod, are prepared as the catalyst supports and assigned to the surface of (100), (111) and (110) crystal plane, respectively. The Ru/CeO 2 (nanorod) exhibits the highest selectivity to CO (97.6 %) at 350 °C, while the Ru/CeO 2 (nanocube) exhibits a mediocre selectivity to CO (41.4 %) but the highest CO 2 conversion. The shape of the CeO 2 support determines the electronic state of supported Ru atoms through the electronic metal-support interaction. The low CO affinity on cationic Ru β sites leads to the higher selectivity to CO on the Ru/CeO 2 (nanorod) and Ru/CeO 2 (nanooctahedron) catalysts, while the strong dissociation ability of H 2 on low valence Ru α sites results in the high activity on the Ru/CeO 2 (nanocube) catalyst.