Low temperature activation and reactivity of CO2 over a Cr(II)-based heterogeneous catalyst: a spectroscopic study.

A new heterogeneous catalyst for CO(2) activation was identified in the Cr(II)/SiO(2) Phillips catalyst, one of the most important catalysts used industrially for olefin polymerization. Interestingly, it was found that Cr(II)/SiO(2) strongly activates CO(2) already at room temperature, making it available for chemicals synthesis. A preliminary attempt in this direction was done by following the reaction of CO(2) with ethylene oxide at room temperature by means of FT-IR spectroscopy, which showed the formation of ethylene carbonate. Besides non-reductive CO(2) activation, Cr(II)/SiO(2) showed good performances in catalytic reduction of CO(2) 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 CO(2) chemical fixation.