Hydrogenation of CO2 to Olefins over Iron-Based Catalysts: A Review

The widespread use of fossil fuels has caused high CO2 concentrations in the atmosphere, which have had a great impact on climate and the environment. Methods for efficiently utilizing CO2 to produce high value-added chemicals have received increasing attention. Among the products of CO2 hydrogenation, olefins, an important petrochemical feedstock, are one of the essential target products. Therefore, CO2 hydrogenation to olefins has been extensively studied, especially for the development of high-performance catalysts. Iron-based catalysts, which are widely used in Fischer–Tropsch synthesis reactions, have also been considered attractive for use in the CO2 hydrogenation to olefins due to their excellent performance in catalytic activity and reaction stability. Most studies have focused on the modulation of morphology; reduction and adsorption properties by tuning the methods of catalyst syntheses; pretreatment conditions and the composition of catalysts, in order to improve hydrogenation activity and olefin yield. In this review, we briefly discuss a thermodynamic overview of the CO2 hydrogenation to olefins reaction, the optimization of catalyst modifications, and current insights into the reaction mechanism; moreover, we summarize current challenges and future trends in the CO2 hydrogenation to olefins.