Ultrasound and microwave prepared Fe-supported catalysts for biosyngas conversion by Fischer-Tropsch

Fischer-Tropsch (FT) synthesis is an industrial method for the production of fuels and chemicals from CO and H2 using cobalt or iron-based catalysts In this work supported iron-based FT catalysts with high loading of active metal have been prepared introducing in traditional impregnation method an innovative ultrasound (US) or microwave (MW) treatment. The role of US and MW is beneficial for the metal deposition, increasing the catalyst activity. FT results have indicated the catalysts prepared by US as the most efficient, particularly when sonication is performed in argon atmosphere. All the samples have been characterized by BET, TPR, SEM, TEM, XRD and microRaman analyses. Iron based catalysts are industrially used in FT synthesis when the feeding is composed by a mixture of H2 and CO not in stoichiometric ratio (i.e. H2/CO < 2) and in presence of CO2 as impurity; the so called biosyngas (i.e. synthesis gas obtained from biomass) has this composition. For this reason these new catalysts were tested in FT reaction using as feeding mixture with different ratios H2/CO and adding in some cases CO2 in different amount. The best catalytic results were obtained using the samples prepared by US in Argon atmosphere.