Weakening the Mn–O–Si Interaction via Carbon Intercalation for the Enhanced Catalytic Ozonation of Refractory Pollutants in Environmental Matrices

The strong metal–support interaction (MSI) has been widely attributed to enhanced catalytic activity. However, this attribution might be wrong in catalytic ozonation, since MSI that is too strong might impede the activation of electron-poor ozone molecules. Herein, we reported a strategy to subtly modulate the Mn–O–Si interaction by intercalating the carbon film between the silica support and active manganese oxide. When using MnO_x/0.5C/SiO₂ with the moderate MSI as a catalyst in the catalytic ozonation of refractory paracetamol (PCM), 91.1 ± 2.4% of PCM was removed within 30 min, about 30% higher than that using the catalyst of MnO_x/SiO₂ with a strong MSI. Moreover, the reaction rate reached 8.01 × 10^–2 min^–1, 2.2 and 1.3 times that with MnO_x/SiO₂ and MnO_x/1C/SiO₂, respectively. Importantly, further integration of MnO_x/0.5C/SiO₂ into membrane filtration achieved high rejections of PCM (>94.3%) under various realistic water scenarios during a continuous 12 h operation, demonstrating strong resistance to environmental matrices interference. Experimental and theoretical evidence revealed that the moderate MSI resulted in the high dispersion of active MnO_x nanoclusters in the size of 2.3–4.4 nm and promoted the adsorption of ozone over MnO_x and its dissociation into surface *O, ^•OH, ^•O₂^–, and ¹O₂ for decontamination. As a constructive work, this study revealed the significance of MSI in catalytic ozonation and offered a simple regulation method for constructing active interfaces of metal-supported catalysts.