Abstract <p>Peroxymonosulphate (PMS) activation via non-radical pathways has emerged as a promising pollutant degradation method owing to its highly selective oxidation of organic pollutants and high tolerance to water matrices. However, the mechanism underlying this non-radical process remains unclear. Herein, we reveal a mechanism for the transformation phenomenon between singlet oxygen (¹O₂) and high-valence Mn species in a spinel MnCo₂O_4.5/PMS system, which aggressively enhances the degradation rate of organic contaminants and dramatically decreases PMS usage. The mechanism of the transformation is due to the increased valence of Mn via the introduction of Co into spinel Mn₃O₄. These results highlight the mechanism of non-radical pathways in water treatment and provide a new strategy for designing catalysts for PMS activation.</p> Graphical Abstract <p></p>