Iranian Journal of Materials Science and Engineering

A series of MAl₂O₄ (M=Ni, Zn, and Cu) aluminates were prepared by using impregnation method; the metal content of the products was ranged between 5wt% to 25wt%. The samples were characterized by x-ray diffraction (XRD), Brunauer Emmett Teller (BET) surface area, NH₃ temperature-programmed desorption (NH₃-TPD), and inductively coupled argon plasma (ICP).

The specific surface areas of zinc, nickel and copper aluminates were in the ranges of 47-77m²/g, 63-87m²/g and 1.6-3m²/g, respectively. The surface acidity decreased in the order of CuAl₂O₄<< NiAl₂O₄< ZnAl₂O₄<< Al₂O₃. By increasing the amount of metals in the samples, the number of acidic sites decreased, but their strength did not significantly change. Ni-aluminates have fewer acidic sites than Zn-aluminates, particularly in strong acid sites