Heterogeneous activation of peroxymonosulfate by LaCo1-xCuxO3 perovskites for degradation of organic pollutants

Recently cobalt-based heterogeneous catalysts have been widely investigated for peroxymonosulfate (PMS) activation in sulfate radical-based advanced oxidation processes. However, the improvement of the catalytic performance for PMS activation remains to be a challenge. As the limiting step, the rapid transformation of Co II /Co III redox pairs is crucial for PMS activation. Perovskites attract increasing attention due to their controllable oxidation state of B-site metal and formation of oxygen vacancies, which accelerates the cycle of redox pairs. LaCo 1-x M x O 3 (M = Cu, Fe and Mn) perovskites as heterogeneous catalysts of PMS were synthesized for the degradation of phenol. The results showed that LaCo 0.4 Cu 0.6 O 3 exhibited the highest catalytic activity. The pseudo first-order kinetic constant of phenol degradation on LaCo 0.4 Cu 0.6 O 3 is 0.302 min −1 , being about 5 times as high as Co 2+ with same molar concentration of cobalt in LaCo 0.4 Cu 0.6 O 3 . XPS analysis confirmed that substitution of copper could promote the cycle of Co II /Co III , thus enhance the catalytic efficiency for PMS activation. The facilitated cycle of Co II /Co III played a crucial role in the generation of sulfate radicals, hydroxyl radicals and singlet oxygen. And sulfate radical was the primary radical responsible for pollutants degradation. The results provide insights into constructing novel perovskite catalysts for the removal of organic pollutants in water.