CaMnO3 perovskite nanocrystals for efficient peroxydisulfate activation

Perovskite oxides ABO(3) with unique structure showed promising performance on persulfates activation. Previous research works mainly focused on Co-based or rare earth metal (La, Sr)-based perovskite oxides for peroxymonosulfate (PMS) activation. Here, we firstly studied perovskite CaMnO3 metal oxide composed with the low cost and eco-friendly Ca and Mn elements for PDS activation. Perovskite CaMnO3 metal oxide achieve the superior catalytic activity for reactive oxygen species generation than the regular Mn oxides (beta-MnO2 and Mn2O3) and other types CaxMnyOz (spinel-type CaMn2O4 and Ca2MnO4) solid solution due to the tolerance of Mn multivalence and defects in the perovskite structure and the excellent Mn3+/Mn4+ redox capacity in CaMnO3. The CaMnO3/PDS system could be applied at a wide pH range from 4 to 12, and exhibited better performance in basic conditions. Different active species including SO4 center dot-, center dot OH reactive radicals and singlet oxygen O-1(2) were found and responsible for effective pollutants degradation. Our study shows eco-friendly perovskites possess great potential in the refractory organic pollutants removal by catalytic activation of PDS.