Phase conversion during MnC2O4pyrolysis and the application on high photothermal catalytic degradation of toluene

Monoclinic Mn5O8, spinel Mn3O4, and perovskite Mn 2O3were prepared by thermal decomposition of MnC2O4. The formation of different MnOx species observed by thermogravimetric analysis (TGA) and X-ray diffraction (XRD) measurements showed temperature-dependent phase transformation following the path of MnC2O 4→Mn5O8→Mn3O4→Mn2O 3occurring during the heat treatment process. Among these manganese oxides, the MO-1 (Mn5O8) showed the best light-driven photothermal catalytic performance reaching up to 99% of toluene degradation and 75% of mineralization efficiencies reached within 30 min. Besides, it is found that structural defects decrease with the increase of the calcinated temperature, and the Mn4+/Mn3+active sites and oxygen vacancies play an important role in improving the light-driven photothermal catalytic performance.