Control of metal-support interaction for tunable CO hydrogenation performance over Ru/TiO 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 (rutile or anatase) and the treatment conditions for the TiO 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 (Ru/r-TiO), while catalysts supported by anatase (a-TiO) showed almost no activity. Characterization confirmed that the SMSI effect could be neglected for Ru/r-TiO, while it is dominant on Ru/a-TiO after reduction at 300 °C, resulting in the coverage of Ru nanoparticles by TiO overlayers. Such SMSI could be suppressed by H treatment of the a-TiO support and the catalytic activity of the as-obtained Ru/a-TiO(H) 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 support determines the SMSI state and catalytic performance of Ru/TiO 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.