Construction of Highly Active Fe5C2–FeCo Interfacial Sites for Oriented Synthesis of Light Olefins from CO2 Hydrogenation

Abstract

The hydrogenation of CO₂ into high-value chemistry is seen as one of the viable strategies for solving the energy crisis of the future. Light olefins have attracted considerable attention as basic feedstocks in the industry. In this work, a series of Fe–Co bimetallic active site catalysts were constructed by a typical sol–gel strategy. The synergistic regulation layout of the Fe–Co bimetallic active site catalyst constructed highly active interfaces and exhibited high conversion (56.9%) of CO₂, low CO selectivity (3.6%), high selectivity (40.5%) of light olefins, and remarkable light olefins yield (22.2%). The results of the associated characterization analysis indicate that the high activity interfaces formed by the synergistic regulation layout of the Fe–Co bimetallic active sites are the fundamental reason for the high yield of light olefins. The high activity interfaces formed by the introduction of cobalt drive the RWGS reaction forward (Le Chatelier’s Principle), which further enhances the CO₂ conversion. In addition, the dynamic evolution of the physical phase structure, elemental composition and valence, CO₂ and H₂ adsorption ability, and the formation process of light olefins during the reaction of Fe–Co bimetallic catalysts were analyzed by in situ DRIFT spectra and other characterizations, and a potential mechanism for the high selectivity of CO₂ hydrogenation to light olefins is further proposed. This work provides an effective and rational design strategy for the synergistic regulation layout of Fe–Co bimetals with highly active interfaces to promote efficient hydrogenation of CO₂ for the oriented synthesis of light olefins.