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.