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

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.