Iron Incorporated Copper/Zinc Oxide Catalysts for Methanol Mixed Hydrocarbons by Fischer-Tropsch Synthesis

From the depletion of oil and gas, the synthesis of methanol and long-chained hydrocarbons from syngas had drawn an attraction as well as the development of catalysts. Phases of iron incorporated copper/zinc oxide (Fe-Cu/ZnO) catalysts, compared to Cu/ZnO, for the preparation of methanol-mixed long-chained hydrocarbons by the Fischer-Tropsch synthesis (FTS) from syngas were investigated. The results from XRD and XAS revealed that the main Fe phases of Fe-Cu/ZnO after preparation, calcination, reduction, and use were Fe(NO3)3, Fe3O4, Fe2O3, and Fe2O3, respectively. The main Cu phases of Fe-Cu/ZnO after preparation, calcination, reduction, and use were Cu(NO3)2, CuO, Cu0, and Cu0, respectively, compared to the main Cu phases of Cu(NO3)2, mixed Cu(NO3)2 and CuO, Cu0, and Cu0, respectively, in the unpromoted Cu/ZnO. From FTS results, increasing the amount of Fe in Fe-Cu/ZnO catalysts would improve the long-chained hydrocarbon selectivity whereas it decreased the methanol selectivity, compared to those of the unpromoted Cu/ZnO, showing that increasing Fe level increased the active sites for CO dissociation with decreasing number of active sites for hydrogen adsorption on the promoted catalysts.