Effect of Iron-Containing Dispersion Preparation Method on the Performance of Three-Phase Hydrogenation of Carbon Oxides

This study investigates, for the first time, how the preparation method of an Fe-containing dispersion effects its catalytic performance in the three-phase hydrogenation of a CO + CO2 + H2 mixture in a continuous stirred-tank reactor (CSTR). The results show that the preparation method influences nanoparticle size: drop thermolysis generates 2–4 nm nanoparticles, whereas flash pyrolysis produces larger particles with a size distribution peaking at 79 nm. Over the entire temperature range tested, the Fe-containing dispersion prepared by drop thermolysis exhibits higher activity (CO conversion up to 62.6%) than that synthesized by flash pyrolysis (49%). The Fe dispersion prepared by drop thermolysis exhibits selectivity toward C5+ hydrocarbons, while that from flash pyrolysis favors methane. This difference arises from distinct active phases: Hägg carbide dominates in drop thermolysis whereas magnetite dominates in flash pyrolysis.