Decomposition of hydrogen peroxide on a mixed NiO-MgO catalyst and the effect of ionizing radiation on the catalyst

Abstract

The decomposition of hydrogen peroxide in aqueous solution was studied on the NiO-MgO two-component catalyst, which occurs as solid solution in the whole composition region (0-100% component fractions). The results indicate that the mutual influencing of the two oxides shows up predominantly in the different amount of oxygen chemisorbed on the surface, which may be due to the different particle size of the various catalysts. The catalytic activity of the samples, being proportional to the amount of chemisorbed oxygen, is thus in a nonlinear relation to the catalyst composition. From the view point of the concept of bivalent catalytic centres, the catalytic activity can be thus assumed to be controlled by the concentration of the minor donor reaction centres constituted by the Ni3+ ions. In addition, catalytic centres of another kind, probably charge one, take part in the catalytic activity of the system in question. The two kinds of catalytic centres can be affected by the temperature of calcination during the preparation of the oxides, their heat treatment, and also by gamma-irradiation of the system. The equilibrium state of the two kinds of catalytic centres is attained rather slowly at room temperature.