Mixed oxides have different surface properties as compared with Al2O3 and MgO. The Point zero charge of γ-Al2O3 increased as the MgO loading was increased and varied between the PZCs of pure oxides of alumina and magnesia.
The increase in the PZC is attributed to the basic nature of MgO. Further, it was noted that low contents of MgO into
alumina didn’t change the phase and structure of γ-Al2O3 however, the effects became dominant at higher loading of
MgO. The surface area, pore volume, pore diameter, decreased as the MgO contents increased due to the plunging
of MgO into the pores of alumina and some oxide reactions on the surface to make some complex oxides.