(106e) The Influence of Co Nanoparticles Distribution In Fischer-Tropsch Co-Supported Catalysts on Selectivity

It’ s known that realistic FT catalysts are characterized by metall particles size distribution. Moreover, as the average particles size and the distribution  during the catalytic process are changing. The distributions parameters of Co particles in Co/Al₂O₃ catalysts (dispersion and average value) were modified by alteration the calcination temperature of (200⁰C – 500⁰C) by Pt promotion and sucrose addition to catalyst at study of preparation and by changing the water vapors pressure [[i]]. For characterization of catalysts the magnetometric method in situ  was employed.  The distributions calculated from  dates of magnetic method are almost the same as received by from TEM’s dates. In this study are showed that increase of temperature calcination result in increase of average Co particles size and the shape of distribution. So the distributions parameters maximum is achieving in 400⁰C [[ii]].  The addition to Co/SiO2 catalyst of Pt and the promotion Co-Ru/SiO2 by sucrose leads to decrease of average Me particles size down to superparamagnetic sizes and the dispersion of distribution [ [iii] ].

       So, it was showed that the width of distribution is principal factor, which influence on FT selectivity. The smaller the width of dispersion, the more C₅₊ - selectivity (1). For Co nanoparticles with diameter less than 6 nm we see the increase of methane catalysts function, but  with diameter more than 6-7 nm the influence of  Me particles size on selectivity is absent.