Carbon dioxide hydrogenation catalyzed by ruthenium complexes immobilized on MCM-41

Two kinds of immobilized Ru catalysts were synthesized by anchoring different ruthenium complexes on the functionalized mesoporous MCM-41 and then characterized with elemental analysis, atomic absorption spectrophotometer, UV-Vis and FT-IR. Hydrogenation of carbon dioxide to formate was investigated over these catalysts in CO2-expanded solvent. High formate yield was obtained but no by-product was detected. The effects of solvents and bases on the catalyst activity were also examined. These two catalysts are different in their activities and stabilities, especially at lower temperature and hydrogen partial pressure. They are promising in industry because of the easiness of catalyst separation and reuse.