Hydrogenation of CO[sub.2] to Olefins over Iron-Based Catalysts: A Review

The widespread use of fossil fuels has caused high CO[sub.2] concentrations in the atmosphere, which have had a great impact on climate and the environment. Methods for efficiently utilizing CO[sub.2] to produce high value-added chemicals have received increasing attention. Among the products of CO[sub.2] hydrogenation, olefins, an important petrochemical feedstock, are one of the essential target products. Therefore, CO[sub.2] 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 CO[sub.2] 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 CO[sub.2] 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 CO[sub.2] hydrogenation to olefins.