Turning waste into value: potassium-promoted Red Mud as an effective catalyst for the hydrogenation of CO2.

Abstract

Since 1887 Red Mud is 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 an important 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. Here, we demonstrate that Red Mud can be turned into an efficient catalyst for the valorization of CO 2 . By a simple potassium promotion, 45% conversion of CO 2 with a light olefin (C 2 -C 4 ) selectivity of 36% has been achieved at 350 ºC, 30 bar and at 9600 mL·g -1 ·h -1 , matching the performance of some of the best catalysts reported to date.