Influence of Fabrication Temperature and Time on Light Olefin Selectivity of Iron–Cobalt–Cerium Mixed Oxide Nanocatalyst for CO Hydrogenation

Abstract

The Fischer–Tropsch synthesis process is a polymerization reaction in which various chain lengths of product can be produced from a mixture of CO and H2 (synthesis gas). A solvothermal technique was used to synthesize magnetic iron–cobalt–cerium mixed oxide nanoparticles. Process variables such as reaction temperature and time can play an important role in a chemical process. The results showed that the optimal preparation time and temperature in order to enhance light olefin (C2–C4) selectivity is 18 h and 120 °C. The effects of experimental variables including temperature (120, 150, 180 °C) and reaction time (10, 14, 18 h) were investigated. The nanoparticles were characterized by X-ray diffraction (XRD), vibrating sample magnetometry (VSM), temperature programed-reduction (TPR), Fourier infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray (EDS), and X-ray photoelectron spectroscopy (XPS). Average crystalline size determined from XRD patterns ranged over 4.5–8.3 nm. The results indicate that reaction temperature and time have marked effects on the magnetic properties of nanoparticles changing from a ferromagnetic behavior to a superparamagnetic one at a reaction temperature of 120 °C. TPR profiles of the nanoparticles synthesized at different temperatures revealed that reducibility shifted to higher temperatures. XPS results verified Fe3+, Co2+, and Ce3+ of oxidation states.

Assessment of composition and calcination parameters in Fischer-Tropsch synthesis over Fe–Mn–Ce/γ-Al2O3 nanocatalyst

“…The results obtained by Maiti et al [32] showed that in iron-manganese catalysts, if manganese content is low the interaction of the metals is significant and the formation of light olefins increases. The positive role of rare-earth metal oxides especially ceria on thermal stability, selectivity and activity of FT catalysts has been confirmed [33]. The studies of Barrault et al [34,35] revealed that addition of CeO 2 as a promoter has been increased CO hydrogenation due to C-O bond weakening.…”