Cu/ZnO Catalysts for Enhancing the Methanol Selectivity in Fischer-Tropsch Synthesis

Abstract

Cu/ZnO catalysts were studied to enhance the methanol selectivity in Fischer-Tropsch synthesis (FTS). By knowing that the methanol production from syngas (CO/H2) accelerated the crystallization of Cu and ZnO and led to the deactivation of the catalysts, a small amount of iron added to the catalyst could improve the catalyst stability by suppressing the crystallization of Cu and ZnO. The promotional effects of iron on the textural properties, reduction behavior, and structural changes of the Cu-based FTS catalysts were investigated by X-ray diffraction (XRD), X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS). Their catalytic activity was measured at 10 bar and 190°C with H2/CO ratio of 2 and the FTS products were analyzed by GC. The product distribution was presented in terms of methanol, C1, C2-C4, and C5+ selectivity.