Synthesis and characterization of ternary nanocomposite of ZnO–CeO2-graphene quantum dot for enhanced visible-light photocatalysis

Abstract

The ZnO–CeO2-GQDs ternary nanocomposite was synthesized via a scalable nebulizing spray pyrolysis technique to achieve high-performance visible-light photocatalysis. Gram-scale graphene quantum dots, hydrothermally synthesized from citric acid, were incorporated into the precursor solution containing Zn2+ and Ce3+ ions. The structural, optical, and electrochemical properties of the nanocomposite were characterized by FESEM, TEM, UV–Vis, PL, and EIS. When applied to the degradation of methyl orange, the ternary photocatalysts demonstrated superior activity, achieving 98.2% degradation within 140 min under visible-light irradiation. Photoluminescence and electrochemical impedance spectroscopy analyses revealed a highly efficient three-level charge transfer mechanism, which drastically suppressed electron–hole recombination. This work provides a practical synthesis route and demonstrates the rational design of ternary composites for efficient environmental remediation