Fig. 1. XRD patterns of (a) CAO product after microwave heating at 600 W for 20 min,
and (b) CAO bulk sample, comparing to the diffraction lines of the references: CuAlO2
(red), CuAl2O4 (green), CuO (blue) and Al2O3 (violet). (For interpretation of the references
to color in this figure legend, the reader is referred to the web version of this
article.)