Advances in the preparation of light alkene from carbon dioxide by hydrogenation

The synthesis of light alkene by CO2 hydrogenation is a strategic technology. In this paper, the thermodynamics, reaction mechanism and catalyst studies of CO2 hydrogenation for the synthesis of low carbon alkene are reviewed. Low-temperature and high-pressure conditions are favorable for the generation of low carbon alkene from the perspective of thermodynamics. Direct hydrogenation of CO2 to prepare low carbon alkene can be divided into inverse water–gas conversion reaction and continuous Fischer-Tropsch synthesis. At present, in the process of preparing light alkene from CO2, reducing the formation of alkanes and improving the selectivity of certain alkene are the focus of research. Different catalysts may have different adsorption forms of CO2, produce different intermediates, and have different reaction mechanisms. Fe-based catalysts have high catalytic activity in the process of CO2 hydrogenation to prepare hydrocarbon chemicals due to their strong water–gas reversion activity. By introducing other components to form bimetallic or multi-metallic catalysts, its catalytic performance is further improved than that of single metal catalysts. The role of the carrier is also not negligible or even very important for the reaction of CO2 hydrogenation to produce light alkene. Electrocatalytic methods can also be used to convert CO2 into low carbon alkene. Since the electrocatalytic reduction of CO2 can be carried out at room temperature and pressure and can be converted to hydrocarbons using cheap Cu and ZnO catalysts, it shows a good prospect for CO2 utilization.