Controlled Thermal Treatment of FeZrOx Catalysts for Enhanced CO2 Hydrogenation to Higher Hydrocarbons

초록

The overall performance of Fe-based catalysts in the direct hydrogenation of CO2 to long-chain hydrocarbons (C5+) is strongly influenced by the nature and electronic properties of metal oxide promoters. This study investigates the effect of calcination temperature on Na-promoted Fe-ZrOx (FZOₓ-y) catalysts synthesized via co-precipitation and thermally reated at temperatures between 400 and 900 oC. The catalyst calcined at 600 oC (FZOx-600) exhibited the highest activity, achieving a CO2 conversion of 44.0% and an unprecedented C5+ yield of 23.0% at 330 oC, 3.5 MPa, an H2/CO2 ratio of 3:1, and a gas hourly space velocity of 4,000 mL g-1h-1. The partial reduction of ZrO2 enhances CO2 adsorption and activation by forming ZrOx species that donate electrons to Fe. The resulting Fe3O4/χ-Fe5C2 dual phases drive the reverse water-gas shift and Fischer-Tropsch reactions, promoting long-chain hydrocarbon formation. These findings demonstrate that calcination-induced electronic modulation of the Fe-Zr interface enables superior CO2 hydrogenation activity and offer a new strategy for designing efficient catalysts for the direct production of liquid fuels and high-value hydrocarbons.

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