Macroporous manganese–cerium oxides boost ozone utilization and mineralization through metal–oxygen bridges

Catalytic ozonation is often limited by inefficient ozone utilization at gas–liquid–solid interfaces and sluggish mineralization of refractory oxidation intermediates. Here, we report a facile and potentially scalable molecular foaming strategy to construct macroporous Mn–Ce binary oxides (HP-MnCeO) that integrate interconnected diffusion pathways with coupled Mn 2+ /Mn 3+ /Mn 4+ and Ce 3+ /Ce 4+ redox cycles. The optimized HP-70MnCeO exhibited enhanced deep oxidation capability, achieving 68% total organic carbon removal during carbamazepine ozonation, while only moderately accelerating parent compound degradation compared with ozonation alone. Compared with mesoporous counterparts, HP-70MnCeO delivered a 1.7-fold higher apparent reaction rate and promoted more efficient transformation of refractory intermediates, despite its lower surface area. It also accelerated ozone decomposition by 6–12 times compared with single-metal oxides, demonstrating improved ozone activation and utilization. Finite element simulations indicate that macropores enhance O 3 and pollutant transport, while density functional theory suggests preferential O 3 adsorption at Mn–Ce bridge sites. HP-70MnCeO maintained stable activity with negligible Mn leaching (0.01 mg/L) during cycling tests and enabled continuous-flow treatment of real wastewater. This work provides a strategy for designing macroporous multimetal oxide catalysts with enhanced mineralization efficiency for practical ozone-based water purification.