Synthesis and Characterization of Fe-Co/meso-HZSM-5: Effect of Impregnated Ratio of Iron and Cobalt

Abstract

The combination of bimetallic Fe-Co (as polymerization catalyst) and HZSM-5 (as cracking catalyst) could convert synthesis gas to biofuel in one-step Fischer-Tropsch synthesis. Mesoporous HZSM-5 gave better conversion, because it increased reactants and products diffusivity. The effect of impregnated ratio of iron and cobalt on characterization of Fe-Co/meso-HZSM-5 catalyst had been studied. HZSM-5 was made from ammonium ZSM-5 through calcination process, then it was desilicated with NaOH and impregnated with 10% metal loading and 0-100% Fe content in Fe-Co (%w). The material results were reduced continuously by hydrogen at 400° for 10 hours. Treatment of HZSM-5 in various ratio of iron and cobalt leads to mesoporosity development. The iron and cobalt impregnation decreased the total surface area from 350.859 m2/g (on HZSM-5) to 231.852-329.606 m2/g (on Fe-Co/HZSM-5). Increasing cobalt content in Fe-Co impregnation on HZSM-5 decreased total surface area and increased average pore diameter. Impregnation process lowered the crystallinity but still maintained the material crystal structure. The catalyst reduction produced Fe, Co, alloy Fe-Co and less oxides of Fe2O3 and Co3O4. The largest alloy Fe-Co could be found in 30Fe-70Co/HZSM-5. Iron and cobalt impregnation occupied the active sites formed from alcohol groups function that was indicated with decreasing alcohol groups area in FTIR spectra.