Enhanced α-olefins selectivity by promoted CO adsorption on ZrO₂@FeCu catalyst

The Fischer-Tropsch (FT) synthesis, as an alternative route to produce high-quality liquid fuels and chemicals, has received considerable attention in recent years. In this work, a nano-sized capsule catalyst (ZrO₂@FeCu) with ZrO₂ as a core and FeCu bimetallic oxide as a shell was fabricated by urea hydrolysis method. For comparison, FeCu@ZrO₂ capsule catalyst was synthesized by the sequential precipitation method. FeCu + ZrO₂ reference catalyst was obtained by physically mixing of FeCu and ZrO₂ samples. Besides, these catalysts with potassium (K) modification were realized by wetness impregnation method, and the catalysts are denoted as ZrO₂@FeCu-K, FeCu@ZrO₂-K, and FeCu + ZrO₂-K, respectively. The structure-function relationship of the obtained catalysts was systematically clarified by means of a series of characterization techniques, such as BET, XRD, H₂-TPR, CO-TPD, XPS, SEM and EDS mapping. Among these catalysts after reduction, ZrO₂@FeCu-K exhibited the most excellent catalytic performance with 97 % CO conversion and 49 % α-olefins selectivity by promoted CO adsorption.