Promoting effects of Cu, Ni, Ru and Pt on Fe-based catalysts in Fischer-Tropsch

The promoting effects of Cu, Ni, Ru and Pt on Fe-based catalysts in Fischer-Tropsch Synthesis were investigated. XRD results indicated that both Cu and Ni can enhance the dispersion of fresh catalysts. XPS results showed that all these metal promoters are enriched on the catalyst surface, whereas four promoters are different in their electronic interaction strength with Fe. H₂-TPR results suggested that Cu, Ru and Pt can be reduced at first to corresponding metal species, which can then promote the reduction of Fe₂O₃ to Fe₃O₄ significantly; however, the influence of Ni on catalyst reduction is of less significance. CO-TPD results illustrated that the addition of the Cu, Pt and Ni can improve the adsorption of CO on the catalysts. The performances of these catalysts in Fischer-Tropsch synthesis was evaluated in a fixed-bed reactor, which indicated that the activity of CO hydrogenation is enhanced through the addition of these metal promoters; the activity of related catalysts follows the order of Fe3Cu > Fe3Pt > Fe3Ni > Fe3Ru > Fe, whereas the selectivity to CH₄ increases in the order of Fe3Ni > Fe3Ru > Fe3Cu > Fe3Pt > Fe.