Enhancing the Fenton-like Catalytic Activity of nFe2O3 by MIL-53(Cu) Support: A Mechanistic Investigation

A novel Fenton-like catalyst was synthesized by immobilizing nano-Fe₂O₃ (nFe₂O₃) on MIL-53(Cu). The pseudo-first-order rate constant of bisphenol A degradation in the nFe₂O₃/MIL-53(Cu)/H₂O₂ system reached 0.0123 min^-1, while the values in MIL-53(Cu)/H₂O₂ and nFe₂O₃/H₂O₂ systems were only 0.0026 and 0.0040 min^-1, respectively. The characterization of nFe₂O₃/MIL-53(Cu) reveals that the supreme catalytic activity of this material could be ascribed to iron-copper synergy, smaller size, and better dispersion of nFe₂O₃ particles. Moreover, a method of trapping Cu(I) by neocuproine was developed, which could shield Cu(I) from interacting with iron and H₂O₂, and thus allow quantitative differentiation of the contribution to the enhanced catalytic activity by each of the factors. Using this method, 19% of the enhancement was determined to be contributed by synergistic effect, while 24% of the enhancement was due to the smaller size and better dispersion of the nFe₂O₃ particles on MIL-53(Cu) support. In addition, the performance of nFe₂O₃/MIL-53(Cu) only dropped 10.7% after five treatment cycles in real wastewater, showing good potential in practical application. We believe this study sheds light on the tailored design of Fenton-like catalysts and elucidates the catalytic mechanisms of supported bimetallic catalysts.