Investigating the deactivation and regeneration mechanism of Fe-based catalysts during CO2 reduction to chemicals

The Modified Fischer-Tropsch process converts CO2 to chemicals using a dual-function Fe-based catalyst composed typically of magnetite and iron carbides. However, catalyst deactivation limits its industrial application. In this study, we combined Density Functional Theory (DFT) calculations and experiments to provide insights into the underlying catalyst deactivation and regeneration mechanisms. The dynamic state of the catalyst was observed with time on stream, revealing the impact of the evolving reaction mixture along the reactor. Rapid CO2 and H2O dissociation on the carbide phase creates persistent *O, causing Fe5C2 deactivation through oxidation. On the other hand, the direct carburization of Fe3O4 proves challenging due to significant energy barriers, underscoring the need for metallic Fe or a highly reduced surface as a precursor to effective catalyst activation. These insights into iron catalyst evolution during CO2 reduction can guide the development of strategies for achieving efficient catalyst performance.