Designing of stable copper ferrite-doped metal–organic framework heterostructure for improved visible light-induced photodegradation of 4-nitrophenol in water

In this study, a copper ferrite (CuF) and cobalt metal–organic framework (CM) composite CuF@CM, was developed via hydrothermal method. The prepared CuF, Co-MOF, and CuF@CM (1:1) composite was characterized by various techniques such as field-emission scanning electron microscope, EDX, X-ray diffraction, BET and attenuated total reflectance-Fourier transform infrared. The catalytic activity of synthesized CuF, Co-MOF, and CuF@CM composites was examined by photodegradation of 4-nitrophenol [4-NP] as a model pollutant under visible light irradiation. The catalytic improvement was achieved by carefully adjusting the mass ratios of CuF to Co-MOF. Among synthesized materials CuF, Co-MOF, and various CuF@CM composites having 1:2, 1:1, and 2:1 weight ratio (CuF:CM), the CuF@CM (1:1) showed exceptional photocatalytic activity in the degradation of 4-NP. Experimental results revealed that the band gap energy (Eg) of CuF@CM (1:1) was 2.2 eV. CuF@CM (1:1) composite achieved 96% efficiency (with a quantum yield of 1.47 × 10^–5 molecules photon⁻¹) to degrade 10 ppm of 4-NP solution (75 min reaction time, pH 6, at 25 ℃, and light intensity of 50-W). Kinetics studies showed that photodegradation of 4-NP by CuF@CM (1:1) followed a first-order reaction rate (R² = 0.972). The synthesized CuF@CM (1:1) nanomaterial also demonstrated superior antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) in visible light as compared to dark. Furthermore, the synthesized CuF@CM (1:1) nanomaterial could be reused at least five times without a significant decrease in its photocatalytic activity.