Metal-nonmetal dual-site cooperative-driven generation of active free radicals and efficient water purification

The generation and regulation of active free radicals are crucial yet challenging in the catalytic ozonation process, which is of great significance. Herein, a novel strategy for the design and synthesis of highly efficient N/C-M x O y /C@Al 2 O 3 (M = Mn, Cu, Mg, Ca, et al.) dual-site catalysts was proposed, and the influence of different metal centers on the generation of active free radicals was elucidated. The N/C-M x O y /C@Al 2 O 3 catalyst demonstrated excellent degradation performance for actual wastewater, such as petrochemical wastewater, achieving a COD removal rate of up to 70 %, which is 15–40 % higher than that of commercially available catalysts of the same particle size. Taking the N/C-Mn x O y /C@Al 2 O 3 catalyst as an example, the interactions between the catalyst, ozone, and organic pollutants were revealed through in-situ IR, EPR, and DFT calculations. The synergistic catalytic mechanism between N/C sites and Mn-OH dual sites was verified, and a regulation mechanism for active free radicals based on site type adjustment (Mn, Cu, Mg, Ca) was proposed. This study uncovered a new reaction mechanism for the catalytic ozonation process under dual-site synergy, providing a novel approach for the development of efficient ozone catalysts and the regulation of active free radicals.