TiO2/CdS nanocomposite stabilized on a magnetic-cored dendrimer for enhanced photocatalytic activity and reusability.

Titanium dioxide (TiO2)-cadmium sulfide (CdS) hybrid nanoparticles on magnetic-cored dendrimers (MCDs) of the zero and first generations (G0 and G1, respectively) were synthesized under hydrothermal conditions. TiO2 was embedded with CdS to produce more radicals and suppress the recombination of photo-induced electrons and holes. A dendrimer with a magnetite core was used as a template to immobilize the TiO2/CdS nanocomposites. They were characterized via scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. The obtained G0- and G1-MCD-TiO2/CdS exhibited high photocatalytic activity and was able to degrade methyl orange (MO) by 83.6 and 88.5%, respectively, in 120 min under ultraviolet irradiation. After 5 cycles, the MO degradation by G0- and G1-MCD-TiO2/CdS was 78.8 and 81.4%, respectively. The MCD-TiO2/CdS materials were easily recycled by applying an external magnetic field. G0-TiO2/CdS was more efficient in photocatalytic performance than G1-TiO2/CdS. Apparent quantum yields (AQYs) and figures of merit (FOMs) were calculated to quantify the photocatalytic performance. The AQYs of G0- and G1-MCD-TiO2/CdS were 3.48 × 10-5 and 3.69 × 10-5 molecules photon-1, respectively. The FOM of our proposed materials demonstrated its high capability for photocatalytic degradation of MO.