Highly Efficient Conversion of CO ₂ to C ₂ –C ₄ Olefins on Co- and Zn-Copromoted Na-Modified Fe ₂ O ₃ Catalysts with Suppressed In Situ Oxidation of Fe ₅ C ₂

High Resolution Image Download MS PowerPoint Slide The hydrogenation of CO 2 to higher hydrocarbons (C 2+ -hydrocarbons), especially to C 2 –C 4 olefins, represents an effective strategy for the high-value utilization of this renewable raw material. Although Fe-based catalysts are typically used for this reaction and demonstrate promising industrial performance, they are prone to deactivation due to H 2 O-mediated oxidation of the catalytically active Fe 5 C 2 phase under reaction conditions. In this regard, we introduce two transition-metal promoters, Co and Zn, to enhance the on-stream stability of Na-modified Fe-based catalysts. The developed Na–Fe 3 Co 1 Zn 1 catalyst achieved a space-time yield of the formation of C 2 –C 4 olefins of 27.6 mmol·g cat –1 ·h –1 at 47.1% CO 2 conversion at 340 °C and 20 bar using an industrially relevant feed. This productivity is about 2 times higher than that of the undoped Na–Fe catalyst and remains stable over 120 h on stream, placing it among the most effective state-of-the-art catalysts reported to date. This catalyst also achieves a higher yield of C 2+ hydrocarbons compared to most previously developed catalysts, while the yields of CO and CH 4, which are side products, are markedly lower.