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

Abstract

• CO 2 −FTS route and the MeOH-mediated route are the two main strategies to convert CO 2 into light olefins in a single step. • Shorter spatial distance between iron oxide and iron carbide inhibit secondary hydrogenation of olefins. • Tandem catalysts containing SAPO-34 plays a major role in maximizing lower olefin yields. • In 2 O 3 /ZrO 2 /SAPO-34 tandem catalyst showed promising results in reducing CO product poisoning. • The key challenges and direction to develop novel catalysts for CO 2 hydrogenation to lower olefins are proposed. Utilizing CO 2 as a carbon source to produce high-value compounds, such as light olefins, is one of the most promising approaches to mitigate CO 2 emissions. Efficient catalysts are critical for optimizing selectivity and yield of light olefins, which is necessary to make the CO 2 -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 CO 2 hydrogenation. There are currently two main strategies to hydrogenate CO 2 into light olefins in a single step: the CO 2 −FTS route and the MeOH-mediated route. The primary objective of the CO 2 -FT approach is to selectively produce the necessary C 2 –C 4 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 C 2 –C 4 olefins. However, obtaining a high productivity of C 2 –C 4 olefins from CO 2 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 CO 2 , owing to their high oxygen vacancies, zeolite topology, and zeolite acidity. Specifically, In 2 O 3 -based formulations are sufficiently promising to get past the drawbacks of traditional iron catalysts. Tandem catalysts with metal oxide In 2 O 3 /ZrO 2 and SAPO-34 components demonstrated promising results in reducing CO product poisoning. This article describes the latest progress, challenges, and prospects for research concerning CO 2 hydrogenation into short-chain olefins using iron-based catalysts and alternative catalysts with multifunctional properties.

Topics & Concepts