Direct carbon dioxide hydrogenation to long-chain α-olefins over FeMnK catalysts

The catalytic hydrogenation of CO2 to high-carbon linear alpha-olefins (LAOs; C >= 4) has gained considerable attention. In this study, FeMnK catalysts were synthesised using an organic combustion method. The introduction of Mn promoted the dispersion of Fe species and enhanced the formation of the iron oxides, whereas the introduction of K promoter led to the formation of iron carbides and improved the carbon chain-growth capability of catalysts. The mechanistic studies revealed that the addition of Mn and K regulated the matching of reverse water gas shift and subsequent Fischer-Tropsch synthesis reactions by enhancing the formation and further conversion of CO intermediate. The selectivity and productivity of LAOs were 45.7 % and 0.236 g center dot g(cat)(-1)center dot h(-1), respectively, under the reaction condition of 320 degrees C, 2 MPa and 20000 mL center dot g(cat)(-1)center dot h(-1). Furthermore, FeMn0.1K0.1 exhibited excellent stability for up to 160-h on stream, demonstrating promising industrial application prospects for CO2 conversion into value-added fuels and chemicals.