Catalytic decomposition of H2O2 over supported ZnO

Transition metal sulfates of Cu(II), Co(II), Ni(II), Cr(III), Mn(II), and F e(III) supported on ZnO were prepared and characterized by SEM, EDX, and XR D. The kinetics of the heterogeneous decomposition of H2O2 over these suppo rted catalysts was investigated. The reaction rate is correlated with both the amount of supported metal ion and its redox potential. The rate of reac tion increases with increasing initial concentration of H2O2, attains a max imum, and decreases thereafter. It also increases with pH and reaches a max imum at high pH values. A reaction mechanism is proposed that implies the f ormation of a peroxo intermediate at the early stages of the reaction. A se cond intermediate is assumed to be formed at high [H2O2](o) which inhibits the progress of the reaction.