Photoelectrochemical and photocatalytic properties of Fe@ZnSQDs/TiO₂ nanocomposites for degradation of different chromophoric organic pollutants in aqueous suspension

Herein, synthesis of a novel nanocomposite comprising titania, iron, and zinc sulfide quantum dots (Fe@ZnSQDs/TiO₂) is demonstrated, and its photoelectrochemical and photocatalytic properties are investigated. The photocatalytic performance is evaluated by studying the degradation of two organic pollutants, Rhodamine B and paracetamol, under both UV and visible light, while photoelectrochemical activity is determined by following water oxidation reaction. The findings indicate that the catalytic performance of ZnSQDs substantially improves after doping with Fe and fabricating heterostructure with TiO₂ nanoparticles, both under UV and visible radiations. The order of photocatalytic performance is discerned to be Fe@ZnSQDs/TiO₂ > TiO₂ > Fe@ZnSQDs > ZnSQDs, while photoelectrochemical is Fe@ZnSQDs/TiO₂ > Fe@ZnSQDs > ZnSQDs > TiO₂. The variation in performance is correlated to electrochemical impedance, optical properties, generation of hydroxyl and superoxide radicals, and transportation of exciton. A mechanism is proposed highlighting the possible charge transfer reaction. [Figure not available: see fulltext.]