Effects of genesis and ionizing radiation on the physicochemical properties and reduction reactivity of NiO-ZnO mixed oxides with hydrogen

Abstract

The physicochemical properties and hydrogen reduction reactivity have been studied for two series of nickel and zinc mixed oxides of various compositions; the two series differ in the genesis of both their major components. It was found that the different absolute values of the physicochemical parameters of the mixed oxides vary with their compositions and depend on the origin of the major components. The changes in the properties of the samples in both series can be correlated with their reduction reactivity as seen by isothermal thermogravimetry in the temperature range 260–500 ° C. Only the series containing zinc oxide in interaction with strongly non-stoichiometric nickel oxide appears to be sensitive to pre-irradiation by γ rays (328 kGy and 3.7 MGy doses) and accelerated electrons (500 kGy dose). The negative effect (a decrease in the rate of reduction) in the region of excess nickel oxide reverses to a positive one (acceleration of reduction) with increasing zinc oxide content, forming a separate phase of the mixed system.