Ozone catalytic oxidation of toluene over triple perovskite-type catalysts modified with KMnO₄

A unique triple perovskite-type catalyst was successfully synthesized using the simple sol-gel approach, and surface acid modification was added to improve the ozone catalytic oxidation (OZCO) process ability to remove toluene more effectively. Our study indicates that La₃MnCuNiO₉ catalyst treated with KMnO₄ shows the best toluene oxidation activity. At 250 °C, the rates of conversion and mineralization were 100% and 83%, respectively, under thermal catalytic system when C₇H₈ concentration = 500 ppm. During the OZCO system ([C₇H₈] = 20 ppm, O₃/C₇H₈=8; room temperature), for 6 h, the conversion rate remained at 100%. The high ratios of Mn⁴⁺/(Mn⁴⁺+Mn³⁺), Cu²⁺, and abundant surface oxygen species, high specific surface area, and pore volume lead to remarkable catalytic performance of this catalyst. Meanwhile, the catalyst contributes to superior stability and water resistance. The catalytic mechanism of La₃MnCuNiO₉ after KMnO₄ treatment in the context of OZCO was further discussed. Overall, after KMnO₄ treatment, the La₃MnCuNiO₉ catalyst reveals extraordinary catalytic activity and excellent stability combination of this catalyst with ozone exhibits high toluene removal efficiency in the OZCO system and has a good potential for industrial applications.