Elucidation of The Influence of Cu Promoter on Carburization Prior to Iron‐Based Fischer‐Tropsch Synthesis: an In situ X‐Ray Diffraction Study

As a prerequisite elementary step, carburization of iron oxides to form iron carbides is critically important to display activity for iron-based Fischer-Tropsch synthesis catalysts. The positive role of the Cu promoter to advocate the reduction of the iron oxides has long been known. Nevertheless, its complex influence along the carburization of catalyst precursors remains controversial. Here, we resolve this decades-long question by using a state-of-the-art insitu X-ray diffraction (XRD) method to elucidate the multi-role of Cu promoter in modulation of carburization rate, composition of post-carburization samples, and morphology evolution of prepared iron carbide particles under CO/He (v/v=2%/98%) and H-2/CO/He (v/v/v=8%/2%/90%) gaseous environment, by excluding the possible interference from promoter components other than Cu. We anticipate that this study enriches current tool box in the research of a specific promoter of the Fischer-Tropsch synthesis catalysts.