Monolayer dispersion of MoO3, NiO and their precursors on γ-Al2O3 Original Research Article

The dispersion capacities of MoO3, NiO and their precursors on the surface of γ-Al2O3 are studied by XPS and XRD techniques. As a relatively low melting point oxide, MoO3 gives a dispersion capacity higher than its precursor molybdate based on mole of MoO3 on γ-Al2O3. Dispersion capacities of molybdate on γ-Al2O3 depend on the pH of molybdate solution used for impregnation while the dispersion capacity of MoO3 on γ-Al2O3 is independent of its precursors. As a high-melting point oxide, the dispersion capacity of NiO based on mole of NiO is the same as that of its precursor. By one-step impregnation, dispersion capacity of nickel nitrate and its derived NiO on γ-Al2O3is larger than that of nickel acetate and its derived NiO. This difference can be attributed to the larger size of nickel acetate molecule. The utmost dispersion capacity of NiO on γ-Al2O3 is achieved through one-step impregnation when nickel nitrate is used as the precursor, while the same capacity can only be achieved through multiple impregnation when nickel acetate is used as the precursor.