Effects of Different Reductive Agents on Zn-Promoted Iron Oxide Phases in the CO2–Fischer–Tropsch to Linear α-Olefins

The pretreatment atmosphere has a significant impact on the performance of iron-based catalysts in carbon dioxide (CO2) hydrogenation. In this study, we investigated effects monoxide (CO), syngas (H2/CO), and hydrogen (H2) during process. To evaluate structural changes after activation reaction, analyzed their morphology particle size, surface bulk phase composition, deposition, desorption linear α-olefins reaction intermediates using transmission electron microscope (TEM), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), diffraction (XRD), Mössbauer (MES), temperature-programmed (TPD), situ diffuse reflectance infrared Fourier transform (in DRIFTS). XPS showed that H2 catalyst caused absence iron carbides due to lack source, CO promoted formation deposits carbides. While mainly consists carbide (FeCx), XRD MES revealed primarily consisted metallic (Fe) oxide (FeOx). composition is closely associated with its at initial stage reaction. olefins C5+ products more encouraged by than catalysts, according DRIFTS evidence. Ethylene (C2H4)/propylene (C3H6)-TPD indicates favorable for which improves selectivity. Based analysis TEM images, stimulated agglomeration sintering. conclusion, results show CO-pretreatment higher activity inclusion FeOX Fe3C. particular, presence Fe3C was found be hydrocarbons. Furthermore, deposition relatively mild conducive maintaining balance FeOx/FeCx surface.