Mechanochemical Synthesis of Ruthenium Cluster@Ordered Mesoporous Carbon Catalysts by Synergetic Dual Templates.

Ruthenium (Ru)@Ordered mesoporous carbon (OMC) is a key catalyst in fine-chemical production. In general, the OMC support is prepared by a wet self-assembly requiring excessive solvent, toxic phenol-aldehyde precursors and a long reaction time, followed by post-immobilization to load Ru species. Herein, we wish to report a solid-state, rapid, and green strategy for the synthesis of Ru@OMC with biomass tannin as the precursor. The chemistry essence of this strategy lies in the mechanical-force-driven assembly, during which tannin-metal (Zn2+ and Ru3+ ) coordination polymerization and hydrogen-bonding interactions between tannin-block copolymer (PEO-PPO-PEO, F127) simultaneously occur. After thermal treatment, Ru@OMC catalysts with mesoporous channels, narrow pore-size distribution (≈7 nm), and high surface area (up to 779 m2  g-1 ) were directed by F127 micelles. Meanwhile, the Zn2+ ions dilute Ru3+ and avoid the sintering of Ru species, resulting in Ru clusters around 1.4-1.7 nm during carbonization (800 °C). Moreover, the Ru@OMC catalyst afforded a good activity (TOF: up to 4170 h-1 ) in the selective oxidation of benzyl alcohol to benzaldehyde by molecular oxygen.