ScholarWorks@성균관대학교

초록

Elucidating the dynamic structural evolution of iron during thermocatalytic CO2 hydrogenation is essential for diagnosing catalyst deactivation and enabling the rational design of durable CO2-to-liquids catalysts. Although active Hägg carbide (χ-Fe5C2) progressively oxidizes to Fe3O4/Fe2O3 in the presence of in-situ formed water, the impact of iron particle size on long-term phase stability remains unclear. Here, Na-promoted FeAlOx catalysts with controlled Fe domain sizes are systematically investigated under industrially relevant conditions to establish a structure–stability–performance relationship. Catalytic behavior is dictated by precursor morphology, which determines the extent of reconstruction during H2 activation and subsequent redox–carburization cycling. Fe domains with an average size of 0.17 μm maintain structural integrity, suppress stress accumulation and limit formation of oxidation-prone fresh surfaces, thereby sustains high C5+ productivity for up to 2000 h on stream. These findings identify iron domain integrity rather than phase identity alone as a decisive descriptor for durability.

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