Size effect of the carbon-supported bimetallic Fe-Co nanoparticles on the catalytic activity in the Fischer-Tropsch synthesis

Carbon-supported bimetallic Fe-Co nanocatalysts with different particle sizes have been synthesized by one-pot method involving simultaneous metal nanoparticles formation and chitosan carbonization. The Fe-Co particle size has been found to vary from 5 to 14 nm depending on the amount of metal loaded in the polymer precursor. For the first time, the size effect of Fe-Co alloy nanoparticles on the specific catalyst activity, yield and selectivity of the products of the Fischer-Tropsch synthesis has been studied. It has been revealed that smaller size of the Fe-Co nanoparticles allows to achieve the maximum selectivity towards C5+ hydrocarbons at lower reaction temperature. The catalyst with the Fe-Co average particle size of 10 nm has been demonstrated the highest specific activity (per unit mass) of 126 μmolCO/(gFe-Co·s). The structure of the Fe-Co bimetallic nanoparticles formed in the composites with different initial metal loading was studied and reviewed for details by XRD analysis.