Control of metal-support interaction for tunable CO hydrogenation performance over Ru/TiO 2 nanocatalysts.

The catalytic behavior of CO hydrogenation can be modulated by metal-support interactions, while the role of the support remains elusive. Herein, we demonstrate that the presence of strong metal-support interactions (SMSI) depends strongly on the crystal phase of TiO 2 (rutile or anatase) and the treatment conditions for the TiO 2 support, which could critically control the activity and selectivity of Ru-based nanocatalysts for CO hydrogenation. High CO conversion and olefin selectivity were observed for Ru/rutile-TiO 2 (Ru/r-TiO 2 ), while catalysts supported by anatase (a-TiO 2 ) showed almost no activity. Characterization confirmed that the SMSI effect could be neglected for Ru/r-TiO 2 , while it is dominant on Ru/a-TiO 2 after reduction at 300 °C, resulting in the coverage of Ru nanoparticles by TiO x overlayers. Such SMSI could be suppressed by H 2 treatment of the a-TiO 2 support and the catalytic activity of the as-obtained Ru/a-TiO 2 (H 2 ) can be greatly elevated from almost inactive to >50% CO conversion with >60% olefin selectivity. Further results indicated that the surface reducibility of the TiO 2 support determines the SMSI state and catalytic performance of Ru/TiO 2 in the CO hydrogenation reaction. This work offers an effective strategy to design efficient catalysts for the FTO reaction by regulating the crystal phase of the support.