Highly Dispersed K- and Pd-Comodified Fe Catalyst for CO2 Hydrogenation to Higher Alcohols

The conversion of CO2 to higher alcohols (HA) is a sustainable way for CO2 utilization, but the development of an efficient catalyst with multifunctional active sites to regulate the C–C coupling process remains a great challenge. Herein, we report a Fe catalyst modified with highly dispersed K and Pd for the efficient synthesis of HA. The optimal 0.3K-1Pd/Fe2O3 catalyst displays the best catalytic performance with an HA STY of 48 mg gcat–1 h–1 at 320 °C, 5 MPa, and 6 L gcat–1 h–1, which is 3.5 times that of 1Pd/Fe2O3 and 35 times that of the 0.3K/Fe2O3 catalyst. We found that in situ generated PdFe alloy and K synergistically stabilize the iron carbide phase, which is responsible for the CO dissociation and alkyl formation, while the PdFe alloy acts as an active site for CO nondissociative activation and CO insertion. Appropriate amounts of K and Pd can regulate the balance of CO* and CHx* species on the catalyst surface, which effectively facilitates C–C coupling to synthesize HA.