Highly selective conversion of H2O2 to 1O2 via three-step electron transfer enabled by in-situ hydroxylation of atomically dispersed high-density Co−N5 sites

The traditional H 2 O 2 oxidation treating high-salt industrial wastewater is confronted with challenges, because of the inhibition of Cl - on oxidant radical. Thus, a non-radical pathway for H 2 O 2 removal of organic pollutants is optional. Herein, an innovative cobalt nitrogen-doped carbon (Co-N 5 -C) catalyst was constructed with an atomically dispersed asymmetrical high-density of Co-N 5 sites and highly active intermediate Co-OH groups, achieving highly selective converting H 2 O 2 to 1 O 2 through three steps electron transfer pathways. The oxidation of tetracycline by ¹O₂ accounted for 95.6 % of the total removal. H 2 O 2 is initially activated at the Co-N 5 site, which generates the active intermediate Co-OH groups. This Co-OH group then further activates H 2 O 2 , leading to the production of •O 2 - /•OOH. The newly produced •O 2 - /•OOH are instantaneously captured by neighboring Co-OH groups and subsequently converted into 1 O 2 . These adjacent catalytic sites could effectively capture and stabilize the short-lived radicals through the distance effect. and the intermediate Co-OH group in the reaction significantly reduces the energy barrier for H 2 O 2 conversion to •O 2 - /•OOH and 1 O 2 conversion by 0.26 eV and 11.12 eV, respectively. The efficiency of tetracycline degradation at 96 % even with the Cl - concentration as high as 7000 mg/L.