ZnAl2O4 and Sn−ZnAl2O4 were synthesized by coprecipitation, sol-gel and impregnation methods. These materials were calcined and treated in H2 at 1073 K. Thermal analysis (DTA and TG), nitrogen physisorption (BET method), X-ray diffraction (XRD) and scanning electron
microscopy (SEM) were used as characterization techniques.
H2 treatment promoted AlxZny crystallization in the coprecipitated and impregnated samples. When tin was added to zinc aluminate, the tin acted as a protective
shell against high-temperature reduction, independently of the preparation technique.