Metal ion-doped CdTe-based quantum dots: preparation, characterization and photocatalytic application

Composite systems of metal-doped CdTe quantum dots (QDs) were synthesized by a simple and fast hydrothermal method. The synthesized nanoparticles of CdTe QDs and three metal ions (Ag, Au and Cu) as dopants were studied using TEM, XRD, EDAX, FTIR and PL. The photocatalytic activity of synthesized QD-based photocatalysts was investigated by removing tetracycline from an aqueous solution under ultraviolet-C light radiation. The incorporation of metals to QDs increases the intensity of photoluminescence (PL) and also causes red shifts in the fluorescence spectrum, resulting in improved photocatalytic properties. The presence of metals with high electron density in their capacitance layer increases the energy of HOMO toward the LOMO, which, in addition to decrease in the band gap, increases the probability of electron excitation of HOMO–LOMO. As a result, the light absorption properties increase and the emission peak shifts toward the longer wavelengths. Results showed that the removal of TC by QD-based photocatalysts followed the pseudo-first-order kinetic model. Finally, it can be concluded that metal-doped CdTe-based QDs photocatalysts can perform well in water remediation processes.