Effective catalysts for hydrogenation of CO2 into lower olefins: A review

Abstract

Utilizing CO₂ as a carbon source to produce high-value compounds, such as light olefins, is one of the most promising approaches to mitigate CO₂ emissions. Efficient catalysts are critical for optimizing selectivity and yield of light olefins, which is necessary to make the CO₂-to-light olefin process economically viable. Therefore, this review focused on various Fe-based catalysts and multifunctional catalysts containing zeolite used for producing short-chain olefins via CO₂ hydrogenation. There are currently two main strategies to hydrogenate CO₂ into light olefins in a single step: the CO₂−FTS route and the MeOH-mediated route. The primary objective of the CO₂-FT approach is to selectively produce the necessary C₂–C₄ olefins, with a focus on the coordination of active metals, promoters, and supports to adjust the surface H/C ratio, which is crucial for the formation of C₂–C₄ olefins. However, obtaining a high productivity of C₂–C₄ olefins from CO₂ hydrogenation requires a significant improvement in activity with inhibiting secondary reactions. Currently, tandem catalysts containing SAPO-34 are currently favoured for the higher production of short-chain olefins from the hydrogenation of CO₂, owing to their high oxygen vacancies, zeolite topology, and zeolite acidity. Specifically, In₂O₃-based formulations are sufficiently promising to get past the drawbacks of traditional iron catalysts. Tandem catalysts with metal oxide In₂O₃/ZrO₂ and SAPO-34 components demonstrated promising results in reducing CO product poisoning. This article describes the latest progress, challenges, and prospects for research concerning CO₂ hydrogenation into short-chain olefins using iron-based catalysts and alternative catalysts with multifunctional properties.