Multi-Promoters Regulated Iron Catalyst with Well-Matching Reverse Water-Gas Shift and Chain Propagation for Boosting CO₂ Hydrogenation

In this work, multi-promoters, including potassium, manganese and titanium, were incorporated into iron catalyst for improving CO₂ hydrogenation and the influences of each promoter were investigated in detail. Besides, the content of each component was optimized to achieve a well-matching tandem catalysis performance between reverse water gas shift (RWGS) reaction and chain propagation reaction. The results showed that the introduction of potassium could improve the RWGS reaction and chain growth capacity by utilizing abundant oxygen vacancy, and strong competitive adsorption. With the further addition of manganese, more active carbides sites with benign dispersion were detected owing to the strong interaction between manganese and iron species. When titanium was added, the catalytic performance of the catalyst was improved by the stronger CO₂ adsorption capacity and longer resistance time of reactants. Therefore, the well-matching catalysis between RWGS and chain propagation was achieved on the corresponding K₃/FeMn₁₀Ti₂₀ catalyst, achieving C₅₊ yield as high as 1282.7 g_fuelkg_cat^-1h^-1 at CO₂ conversion of 44.9 % and maintaining a rather low by-products selectivity (9.6 % for CO, 12.8 % for CH₄).