Enhanced Catalytic Ozonation for Water Treatment via TiO2-Modified LaMnO3 Undergoing Efficient Mn3+/Mn4+ Redox Cycle

The TiO2-modified LaMnO3 catalyst demonstrated outstanding catalytic performance across a broad pH range (4.2 to 10.0) and under various complex water conditions. It achieved complete degradation of the ibuprofen parent compound, attaining an 85.9% mineralization rate. The efficacy stems from the reversible Mn3+/Mn4+ redox couple. The ratio of Mn3+/Mn4+ was 3.9 for TiO2-modified LaMnO3, significantly higher than 1.2 for nanocast LaMnO3. Experimental results and density functional theory revealed that La and Ti did not actively participate in the catalytic ozone reaction. Notably, the Mn3+/Mn4+ pair emerged as key drivers in the involvement of HO•, O2•−, and 1O2 in the reactive oxygen species pathway. Notably, ozone exhibited preferential adsorption and activation on the (010) crystal face of the catalyst. A moderated reduction in interaction forces facilitated the Mn3+/Mn4+ redox cycle, resulting in increased production of reactive oxygen species. These findings contributed to the development of more efficient catalysts for environmental remediation.