Blue CoAl2O4 spinel via complexation method

Cobalt-aluminate spinel, CoAl2O4, has been synthesized by two synthesis variants of the complexation method: tartarate and gluconate routes. The complex precursors have been characterized by IR, UV–vis spectroscopy and thermal analysis. The cobalt-aluminate spinel has been investigated by XRD, IR, UV–vis and luminescence spectroscopy and TEM. The results indicated that in both cases the single-phase nanocrystalline CoAl2O4 spinel was formed. The average crystallite size from TEM images was in the range 50–60 nm. The emission spectra of CoAl2O4 in the visible region confirmed the presence of tetrahedral coordinated Co2+ ion.