Synthesis of highly effective CuO–FeSe₂ composites for the photodegradation of RhB under visible light

The release of industrial effluents into fresh water is a major contributor of water contamination. Therefore, it is highly desirable to develop a viable solution to this alarming issue to improve the quality of clean water. To enhance the photocatalytic efficiency and hence utilization ratio of CuO, a series of CuO–FeSe₂ composites with different varying contents of FeSe₂ were prepared through facile synthetic methods. X-ray diffraction (XRD) and energy-dispersive X-rays (EDX) analysis verified that the samples were successfully prepared without any contaminating phases. The average crystallite sizes of CuO and FeSe₂ were computed to be 29 and 21 nm respectively. For the CuO–FeSe₂ composites, the crystallite sizes varied between 25 and 27 nm. The morphology of CuO was comprised of needle-shaped structures, whereas that of FeSe₂ was observed to be flower-shaped structures comprising of irregular crystals. A red shift in the bandgap of CuO–FeSe₂ composites was observed with the increase in FeSe₂ concentration. The prepared photocatalysts were utilized to evaluate their efficiency under visible light against Rhodamine B (RhB). Among all the prepared composites, CuO–75% FeSe₂ revealed a remarkable performance and degraded 96% RhB in 180 min. Rate constants for the degradation of the dye were determined by applying the Langmuir–Hinshelwood model.