Dark catalytic reduction of CO2 over Prussian blue-deposited TiO2 and the photo-reactivation of the catalyst

The catalytic reduction of CO₂ has been performed over Prussian blue-deposited TiO₂ particles, and the products were methanol, ethanol, acetaldehyde and acetone with a negligibly small amount of methane. The deposition of Prussian blue (PB) onto TiO₂ particles was accomplished under the irradiation of light, and on this occasion PB was further reduced to ES (reduced form of PB). The hydrogenation Of CO₂ taking place in dark was caused by the reaction with active hydrogen atoms generated in the redox reaction consisting of the oxidation of ES to PB and the reduction of H₂O. The deactivated catalyst was restored in KCl aqueous solution under the illumination of light by photo-rereducing PB to ES.