Mn-MIL-100-Derived CuO/Mn2O3-Mn5O8 Composite Catalysts for Benzene Oxidation: Synergistic Effect and High Performance.

A series of octahedral CuO/Mn2O3-Mn5O8 catalysts were prepared through the pyrolysis of Cu-immobilized Mn-MIL-100 and applied to the catalytic oxidation of benzene. The CuO content was identified to be a critical factor governing the physicochemical properties and, consequently, the catalytic activity. All CuO-modified catalysts demonstrated superior activity compared to the Mn2O3-Mn5O8, which can be ascribed to their enriched surface-active oxygen species, higher concentration of oxygen vacancies, and improved low-temperature reducibility. The 4% CuO/Mn2O3-Mn5O8 catalyst emerged as the optimal formulation, exhibiting the highest activity, achieving a T90 of 254 °C. The catalyst exhibited consistent activity through six consecutive reaction cycles. In situ DRIFTS analysis further revealed that benzene oxidation proceeds through the following reaction pathway: benzene → benzoquinone → maleate → acetate → CO2 + H2O.