The development of a heterogeneous catalyst with high catalytic activity and durability for H2O2-mediated oxidation is one of the most important industrial and environmental issues. In this study, a Mn(II)-doped TiO2 heterogeneous catalyst was developed for H2O2-mediated oxidation. The TiO2 substrate-dependent partial-redox behavior of Mn was identified on the basis of our density functional theory simulations. This unique redox cycle was induced by a moderate electron transfer from Ti to Mn, which compensated for the electron loss of Mn and finally resulted in a high-efficiency cycling of Mn between its oxidized and reduced forms. In light of the theoretical results, a Mn(II)-doped TiO2 composite with well-defined morphology and large surface area (153.3 m2 g-1) was elaborately fabricated through incorporating Mn(II) ions into a TiO2 nanoflower, and further tested as the catalyst for oxidative degradation of organic pollutants in the presence of H2O2. Benefiting from the remarkable textural features and excellent Mn cycling property, this composite exhibited superior catalytic performance for organic pollutant degradation. Moreover, it could retain 98.40% of its initial activity even in the fifth cycle. Our study provides an effective strategy for designing heterogeneous catalytic systems for H2O2-mediated oxidations.
Keywords: H2O2-mediated oxidation; Mn(II)-doped TiO2; heterogeneous catalyst; high catalytic activity and durability; partial redox.