The novel alumina/CQDs nanocomposites for modifying optical and structural properties of alumina nanostructure.

This study reports the successful synthesis of novel nanocomposites based on aluminum oxide (Al2O3) utilizing a surfactant-free co-precipitation method. The effect of calcination at 550 °C on the properties of the synthesized nanocomposites is also investigated. Carbon quantum dots (CQDs) are synthesized in a liquid state through a straightforward procedure. Furthermore, alumina/CQD nanocomposites are fabricated by incorporating liquid CQDs during the co-precipitation synthesis of alumina nanoparticles. The results indicate that the optical and structural properties, morphology, and stability of alumina nanoparticles are influenced by forming the nanocomposite, and the calcination process at 550 °C affects the properties of the as-synthesized alumina/CQD nanocomposites significantly. Small spherical nanoparticles and strand-like nanostructures are formed in the calcined nanocomposite with an average diameter and strand thickness of 8.31 nm and 3 nm, respectively. The as-synthesized and calcined nanocomposites exhibit high reflectance from 300 to 1200 nm and can thus be used as broad-range reflectors. Also, the specific surface areas (SSAs) of the as-synthesized and calcined nanocomposites are 214.33 m2/g and 257.63 m2/g, respectively, indicating that high-specific-surface-area alumina/CQD nanocomposites are achieved using the developed synthesis method.