Turning Waste into Value: Potassium-Promoted Red Mud as an Effective Catalyst for the Hydrogenation of CO2

Abstract

Since 1887, red mud has been an unavoidable waste derived from the production of alumina in the Bayer process. Because of its high alkalinity and metal loading, red mud disposal and storage constitute a significant environmental risk. With worldwide storage capacity reaching its limits and no alternatives to the Bayer Process, the development of methods for the valorization of red mud is a must. In this study, red mud is converted into an efficient catalyst for the valorization of CO2. By simple potassium promotion, 45 % conversion of CO2 with a light olefin (C2–C4) selectivity of 36 % is achieved at 375 °C, 30 bar, and 9600 mL g−1 h−1, matching the performance of some of the best catalysts reported to date.