RADIATION INFLUENCING OF THE REACTIVITY OF NIO-BI2O3 MIXED OXIDES DURING THEIR HYDROGEN REDUCTION

The basic physico-chemical properties of NiO-Bi2O3 mixed oxides of var ious composition and their chemical reactivity during hydrogen reducti on as a test reaction were studied. The reduction rate was found to be a nonmonotonic function of composition of the samples which can be po sitively affected by heat treatment in various atmospheres. Gamma-prei rradiation of the system in air with a dose of 1 MGy led to an acceler ation in the process of reduction, whereas irradiation of the samples in water suspension with the same dose caused a conspicuous decrease i n the reduction rate. The sensitivity of the mixed oxides under study towards heat treatment and ionizing radiation, as well as their reacti vity in general, decreased with increasing content of Bi2O3. The negat ive radiation effect appears to be correlable with an increase in surf ace oxidation ability, whereas positive influencing of the reduction r ate can be correlated with an increased concentration of stabilized ch arge defects (non-equilibrium electrons), enhancing the reactivity of an interface.