Investigation of the synthesis and the effect of precursor ratio of Al/Zn on annona squamosal‐like mesoporous particles ZnAl2O4

Abstract

AbstractZinc aluminate ZnAl2O4 particles were synthesized using a spray pyrolysis technique. Aerosol droplets of the mixture of the zinc nitrate with concentration varied from 0.03 to 0.3 M and aluminum nitrate from 0.06 to 1.2 M were pyrolyzed in air at temperatures ranging from 600 to 800°C. The molar ratio of Al to Zn was in the range of 2–4. The produced ZnAl2O4 powders in single spinel phase have the primary and secondary particle sizes in the range of 10–30 nm and 0.5–7 μm, respectively. The primary particle size increased with the reaction temperature but decreased with precursor concentration (PC). The relative density of the particles increased with reaction temperature but decreased slightly with solution concentration at the constant pyrolysis temperature of 800°C. Particles synthesized under high PC with the molar ratio of Al/Zn equal to 4 tend to have an annona squamosal‐like exterior appearance but essentially mesoporous interior structure, with the highest surface area to 97 m2/g. The single spinel phase of ZnAl2O4 particles synthesized with molar ratios of Al/Zn equal to 3.5 or 4 may be explained by the increased solid solubility of Al in the ZnAl2O4 structure due to the nanosize effect.