Promotion of iron-oxide with potassium as optimization of the soot combustion catalyst

In this work the effect of potassium addition to iron oxides (FeO, Fe3O4, Fe2O3) as catalysts for soot combustion was investigated. While the addition of potassium by impregnation had positive effect on all oxides the strength of this effect varied considerably. Comparison with potassium ferrites (K2Fe22O34, KFeO2), with potassium as a part of a crystal lattice, proved that they were more active than unpromoted oxides. The determined range of activity was as follows: FeO < Fe3O4 Fe2O3 K/Fe34 ~ K2Fe22O34 K/Fe2O3 K/FeO ~FeO2.