Temperature-driven La2CO5/CN in catalytic ozonation: multi-site reinforcement toward wastewater purification

Single active site and insufficient stability of ozone catalysts are the main bottlenecks limiting their catalytic effect. The stabilization of active sites and construction of multiple sites can be achieved by the precise regulation of the heat treatment temperature during material synthesis. In this study, based on a temperature-mediated crystal phase modulation strategy for the potentially efficient ozone catalyst doping component La, La 2 CO 5 -N-C-600 catalysts were successfully prepared, which had excellent performance in catalysing the ozone degradation of N-diethyl-3-methylbenzenemethanamine (DEET), with a degradation efficiency 22.3 times higher than that of La-CN-550. Combining experimental characterization and density-functional theory calculations, this study systematically elucidates the catalytic mechanism of different La morphologies, focusing on revealing the dual functions of the La 2 CO 5 crystalline phase in La 2 CO 5 -N-C-600. On the one hand, the surface-abundant -OH acts as a Lewis acid site that promotes ozone adsorption and electron transfer. on the other hand, the stable and enriched C=O functional group of this crystal phase can catalyse O 3 decomposition. The two act as synergistic active centres to drive the chain decomposition of ozone and efficiently generate reactive oxygen species (•OH and O 2 •− ). In this study, the temperature-mediated crystal phase engineering and precise regulation of surface functional groups provide a novel route for the targeted construction of active sites of ozone catalysts. Moreover, it lays a theoretical foundation for investigating the regulation of catalytic performance and reaction mechanism by controlling the synthesis temperature.