Radiation effects on the activity of ferric oxide catalysts for the decomposition of hydrogen peroxide

The catalytic and some physico-chemical properties of a variety of ferric oxides have been studied. Most of the catalysts prepared consisted of hematite and magnetite. The specific catalytic activities of the samples were found to be very different and their values appeared not to be determined by the ratio of the hematite and the magnetite present in the sample. Heat treatment of the samples changed their catalytic efficiency. γ-Irradiation (60Co) of the catalysts with the dose of 1 MGy led to a lower catalytic activity, β-irradiation (90Sr-90Y) with a dose of 10 kGy enhanced their catalytic efficiency and a neutron-irradiation (252Cf) with the dose of 425 Gy generated positive or negative radiation catalytic effects. The observed changes in catalytic activity of the treated samples may be explained in terms of the principle of bivalent catalytic sites provided that the surface concentration of the Fe2+-Fe3+ sites determined the catalytic activity of the ferric oxide. (author)