Effect of preparation method, loading of Co3O4 and calcination temperature on the physicochemical and catalytic properties of Co3O4/ZnO nanomaterials

ZnO nanomaterials (ZnOT, ZnOS and ZnOP) were successfully synthesized by thermal decomposition, sol–gel auto combustion and precipitation methods, respectively. Co3O4/ZnO catalysts were synthesized by impregnation method, nominated as CoZnOT, CoZnOS and CoZnOP, respectively. The as-prepared catalysts were characterized by XRD, N2 adsorption–desorption isotherms, HR-TEM and FT-IR techniques. The SBET of CoZnO nanomaterials were significantly higher than those of the pure oxides. Further, the Co3O4/ZnO sample in which ZnO synthesized via sol–gel combustion using citric acid (CoZnOSCI) showed the largest surface area while CoZnOP sample showed the smallest value. The HR-TEM images showed that addition of Co3O4 to ZnO catalyst and the calcination temperature affected the morphology. The catalytic decomposition of H2O2 of the Co3O4/ZnO catalysts is higher than that of the pure oxides. The most catalytically active sample is Co3O4/ZnO in which ZnO synthesized via thermal decomposition of zinc carbonate (CoZnOTC) while CoZnOSCI catalyst being the less active one. [Display omitted] •ZnO catalysts prepared by thermal decomposition, sol–gel and precipitation methods.•Co3O4/ZnO catalysts prepared by impregnation method using different zinc precursors.•The SBET of Co3O4/ZnO catalysts were much higher than those of the pure oxides.•The decomposition of H2O2 of Co3O4/ZnO catalysts is higher than of the pure oxides.•The addition of Co3O4 to ZnO catalyst modified the morphology.