Synthesis of single-phase ZnAl2O4 nanoparticles via a wet chemical approach and evaluation of crystal structure characteristics

Single-phase ZnAl2O4 nanoparticles were hydrothermally synthesized utilizing improvements to the preparation of the precursor materials. This synthesis differs from more general syntheses of ZnAl2O4 nanoparticles in that it minimizes the presence of ZnO impurities. The higher purity of our ZnAl2O4 nanoparticles allowed for more comprehensive X-ray diffraction analysis as well as more sensitive spectroscopic evaluation. Moreover, pH control of the precursor solution dramatically improved the reproducibility of the synthesis. The lattice constant of the ZnAl2O4 samples synthesized by our technique is different from what is observed in particles fabricated using more common solid state reactions. This difference in lattice constants indicates the occurrence of a site exchange phenomenon between Zn2+ and Al3+ and/or oxygen deficiency. This suggests the possibility of tailoring novel functional spinel oxides for a wide array of future applications.