Mn−Fe Dual-Metal Assemblages on Carbon-Coated Al2O3 Spheres for Catalytic Ozonation Oxidation: Structure, Performance, and Reaction Mechanism

Graphical We designed a carbon-coated aluminum oxide carrier and reinforced it with Mn−Fe bimetal assemblages to prepare a high-performance catalyst Mn−Fe/C-Al 2 O 3 . Mn−Fe/C-Al 2 O 3 catalyst exhibited satisfactory catalytic ozonation activity and stability in the degradation of p -nitrophenol. Experiments and theoretical calculations revealed the internal degradation mechanism of the Mn−Fe/C-Al 2 O 3 catalyst, underscoring the role of the carbon-coated and bimetallic active unit in O 3 activation. Catalysts with high catalytic activity and low production cost are important for industrial application of heterogeneous catalytic ozonation (HCO). In this study, we designed a carbon-coated aluminum oxide carrier (C-Al 2 O 3 ) and reinforced it with Mn−Fe bimetal assemblages to prepare a high-performance catalyst Mn−Fe/C-Al 2 O 3 . The results showed that the carbon embedding significantly improved the abundance of surface oxygen functional groups, conductivity, and adsorption capacity of γ-Al 2 O 3 , while preserving its exceptional mechanical strength as a carrier. The prepared Mn−Fe/C-Al 2 O 3 catalyst exhibited satisfactory catalytic ozonation activity and stability in the degradation of p -nitrophenol (PNP). Electron paramagnetic resonance (EPR) and quenching experiments reveal that radical ( ⋅ OH and ⋅ O 2 ⋅ ) and nonradical oxidation ( 1 O 2 ) dominated the PNP degradation process. Theoretical calculations corroborated that the anchored atomic Fe and Mn sites regulated the local electronic structure of the catalyst. This modulation effectively promoted the activation of O 3 molecules, resulting in the generation of atomic oxygen species (AOS) and reactive oxygen species (ROS). The economic analysis on Mn−Fe/C-Al 2 O 3 revealed that it was a cost-competitive catalyst for HCO. This study not only deepens the understanding on the reaction mechanism of HCO with transition metal/carbon composite catalysts, also provides a high-performance and cost-competitive ozone catalyst for prospective application.