Activity Trends and Mechanisms in Peroxymonosulfate‐Assisted Catalytic Production of Singlet Oxygen over Atomic Metal‐N‐C Catalysts

We synthesized a series of carbon‐supported atomic metal‐N‐C catalysts (M‐SACs: M=Mn, Fe, Co, Ni, Cu) with similar structural and physicochemical properties to uncover their catalytic activity trends and mechanisms. The peroxymonosulfate (PMS) catalytic activity trends are Fe‐SAC>Co‐SAC>Mn‐SAC>Ni‐SAC>Cu‐SAC, and Fe‐SAC displays the best single‐site kinetic value (1.65×105 min−1 mol−1) compared to the other metal‐N‐C species. First‐principles calculations indicate that the most reasonable reaction pathway for 1O2 production is PMS→OH*→O*→1O2; M‐SACs that exhibit moderate and near‐average Gibbs free energies in each reaction step have a better catalytic activity, which is the key for the outstanding performance of Fe‐SACs. This study gives the atomic‐scale understanding of fundamental catalytic trends and mechanisms of PMS‐assisted reactive oxygen species production via M‐SACs, thus providing guidance for developing M‐SACs for catalytic organic pollutant degradation. A series of carbon‐supported atomic metal‐N‐C catalysts with similar structural and physicochemical properties were synthesized to uncover the activity trends and mechanisms in peroxymonosulfate‐assisted reactive oxygen species production. Fe‐SAC displays the best single‐site kinetic value (1.65×105 min−1 mol−1), and the PMS→OH*→O*→1O2 is the most reasonable 1O2 reaction pathway.