Photo-Fenton degradation on Mo-doped NiFe₂O₄ photocatalyst

The poor photo-Fenton properties of NiFe₂O₄, a magnetic material, can be altered by appropriate metal ion doping. We carried out preliminary DFT and TD-DFT calculations and found that the photoexcited molybdenum doped NiFe₂O₄ interacts effectively with H₂O₂ for hydroxyl radical generation. Based on this prediction, we prepared Mo-doped NiFe₂O₄ and tested its photo-Fenton activity for tetracycline (TC) degradation. The Mo-doped NiFe₂O₄ nanoparticles were significantly finer in size and superparamagnetic, enabling easy after-use separation. Experimental and DFT calculation results showed that the Mo-dopant substitutes the Fe³⁺ occupying the octahedral site in NiFe₂O₄. Mo-doping extended the absorption edge and decreased the interfacial charge transfer resistance of NiFe₂O₄. The Mo-doped NiFe₂O₄ nanoparticles demonstrated excellent TC photo-Fenton degradation activity, along with appropriate recyclability. A combination of experimental and DFT calculation results indicated the possible photo-Fenton mechanism.