Developing Multifunctional Fe-Based Catalysts for the Direct Hydrogenation of CO[sub.2] in Power Plant Flue Gas to Light Olefins

The hydrogenation of carbon dioxide (CO[sub.2] ) to produce light olefins is one of the most promising ways to utilize CO[sub.2] in power plant flue gas. However, the low concentration of CO[sub.2] (~10%) and the existence of water steam in the flue gas pose great challenges for the catalyst design. To address these problems, we introduced a Mg promoter and hydrophobic component into the Fe-based catalyst to improve the CO[sub.2] adsorption capacity and weaken the negative effects of water. The yield of light olefins on an optimized multifunctional Fe-based catalyst increased by 37% in low-concentration CO[sub.2] hydrogenation with water steam. A variety of characterizations proved that the Mg promoter played critical roles in regulating the adsorption capacity of CO[sub.2] , increasing the surface electron density of Fe species, and promoting the formation of iron carbide active sites. The hydrophobic component mainly contributed to constraining the oxidation of iron carbides via water steam. It benefited from the rational design of the catalyst, showing how our multifunctional Fe-based catalyst has great potential for practical application in CO[sub.2] utilization.