Decomposition of H2O2 on Pure and ZnO-Treated Co3O4/Al2O3 Solids

The effects of Co3O4 loading, precalcination temperature and ZnO treatment on the catalytic properties of the Co3O4/Al2O3 system were investigated. The amounts of Co3O4 were varied between 5.57 wt% and 32.0 wt% and the resulting solids subjected to heat treatment at temperatures in the range 400–600°C. The amounts of ZnO were varied between 0.36 wt% and 2.12 wt%. The results obtained indicated that ZnO treatment of Co3O4/Al2O3 solids followed by precalcination at 400°C resulted in a progressive decrease in the particle size of the Co3O4 crystallites in the resulting samples.The catalytic activity of such solids towards H2O2 decomposition decreased progressively as the precalcination temperature employed was increased in the range 400–600°C. The relationship between the catalytic activity expressed as a plot of the reaction rate constant, k, versus the amount of Co3O4 in the samples showed a progressive increase in the range 5.6–17.7 wt% followed by an abrupt increase when the extent of loading exceeded th...