Redox potentials of pollutants determining the dominate oxidation pathways in manganese single-atom catalyst (Mn-SAC)/peroxymonosulfate system: Selective catalytic mechanisms for versatile pollutants

Versatile persulfate-based catalytic mechanisms induced by highly-effective single atom catalysts (SACs) have been intensively reported, which was mainly ascribed to the versatile coordinated-structures of SACs. However, the origin of these different mechanisms from the specific properties of pollutants has been ignored. In this work, eight kinds of pollutants were selected and the half-wave potential (φ1/2) values representing their redox potentials were determined. A good correlation between the redox potential characteristics of pollutants and their oxidation performances/pathways in manganese single-atom catalyst (Mn-SAC)/PMS system can be confirmed. The φ1/2 values of different pollutants showed a good correlation with the energy gaps between the pollutants and Mn-SAC/PMS complexes as well as their electrophilicity indexes, which confirmed the redox potential of pollutants was essential to the electron-transfer oxidation in Mn-SAC/PMS system. Based on the new insights in this work, we will be able to unveil the sources of Fenton-like systems with tunable oxidation processes.