A new generation pathway of singlet oxygen in heterogeneous single–atom Mn catalyst/peroxymonosulfate system

The function of heterogeneous catalyst in singlet oxygen (1O2) generation under acidic and neutral conditions and the effect of sulfate radical on the generation of 1O2 is still unclear. This study provided a novel generation pathway of 1O2 in the heterogeneous Mn single − atom catalyst (Mn SAC)/peroxymonosulfate (PMS) system. The MnN4 site with the ideal binding strength promoted the activation of PMS to generate sulfate radical (SO4•–), which would be adsorbed on the carbon/nitrogen sites forming SO4•–(s), reacting spontaneously to produce 1O2. The presence of MnN4 and carbon/nitrogen structure sites could shift the oxidation process from a bulk–phase oxidation to a surface oxidation. This shift has important implications in terms of reaction rate and product distribution, as the dual reaction sites decrease the required migration distance for the active species to form 1O2, avoiding the pointless consumption of active substances.