Low temperature activation and reactivity of CO2 over a CrII-based heterogeneous catalyst: a spectroscopic study

Abstract

A new heterogeneous catalyst for CO₂ activation was identified in the Cr^II/SiO₂ Phillips catalyst, one of the most important catalysts used industrially for olefin polymerization. Interestingly, it was found that Cr^II/SiO₂ strongly activates CO₂ already at room temperature, making it available for chemicals synthesis. A preliminary attempt in this direction was done by following the reaction of CO₂ with ethylene oxide at room temperature by means of FT-IR spectroscopy, which showed the formation of ethylene carbonate. Besides non-reductive CO₂ activation, Cr^II/SiO₂ showed good performances in catalytic reduction of CO₂ to CO, when heated under mild conditions or irradiated with UV-Vis light. Both, in situ FT-IR and UV-Vis spectroscopy, were applied to highlight the redox process occurring at the Cr centres. These results open interesting perspectives to be developed in the field of CO₂ chemical fixation.