Synergistic effect of Cu:Zn-In-Se2 QDs/Fe3O4 hybrid mesoporous films optimization and magnetic fields for solar-driven wastewater purification

Photocatalysis has garnered substantial interest as a cost-effective, eco-friendly method for degrading pollutants from pharmaceutical industries and agricultural sectors. However, the low efficiency of available photocatalysts due to fast recombination and slow separation of photogenerated carriers, demands the design of new photocatalysts that can contribute to solving the current environmental remediation challenges. In this work, we have developed for the first time novel hybrid photocatalysts of colloidal eco-friendly quantum dots (QDs) Cu:Zn-In-Se 2 QDs decorated on one-dimensional (1D) Fe 3 O 4 nanorods mesoporous film on conducting glass substrate and tested the photocatalytic degradation of methylene blue (MB) in the presence of external magnetic field (MF). By optimizing hybrid heterostructure photocatalyst and external MF, an excellent photocatalytic efficiency of 99.96 % photocatalytic removal of MB was achieved, which is 49 % higher than the control photocatalyst Fe 3 O 4 (67.01 %). The significant increase in photocatalytic efficiency attributed to the synergistic effect of broad light absorption of Cu:Zn-In-Se 2 QDs∕Fe 3 O 4 and efficient carrier dynamics assisted with Lorentz force in the presence of external MF. Lorentz force associated with external MF leads to the efficient separation and transport of the photogenerated carrier in hybrid Cu:Zn-In-Se 2 QDs∕Fe 3 O 4 photocatalyst confirmed by time-resolved spectroscopy. Additionally, this novel hybrid photocatalyst was employed as a thin film conducting glass, which demands less materials compared to photocatalysts used in powder form, and has an excellent reusable efficiency after four cycles, demonstrating superior stability and, thus, a promising photocatalyst for real-time wastewater remediation technology. • Developed Cu:Zn-In-Se₂ QDs/Fe₃O₄ nanorod mesoporous films hybrid photocatalyst. • Achieved 99.96 % MB removal under external magnetic field. • External magnetic field enhances charge separation/transport via Lorentz force. • Time-resolved spectroscopy confirms improved carrier dynamics in hybrid film. • Thin film design uses less material and offers high reusability.