Mechanochemical Synthesis of Ruthenium Cluster@Ordered Mesoporous Carbon Catalysts by Synergetic Dual Templates. Issue 36 (24th May 2019) - Wang, Li
Abstract: 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 (Zn 2+ and Ru 3+ ) 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 m 2 g −1 ) were directed by F127 micelles. Meanwhile, the Zn 2+ ions dilute Ru 3+ 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. Abstract : Selective oxidation : This work shows the one‐step mechanochemical synthesis of Ru@ordered mesoporous carbon catalysts by synergetic dual templates. Besides the triblock copolymer F127 (PEO‐PPO‐PEO) as a soft template, Zn(OAc)2 together with Ru 3+ ions were added to strengthen tannin‐based backbone, while the metallic Zn evaporated during carbonization (see figure).