Decipher the key role of ketone toward singlet oxygen evolution in Fenton-like process for water decontamination

Persulfate-based Fenton-like processes are often unsatisfied on the remediation of the complex mediums because the active species of free radicals have usually short lifetime (only 1 µs for hydroxyl radical) or poor selectivity to abatement of the targeted organics. Herein, we report an oxygen-doped carbon catalyst prepared by simple pyrolysis means for persulfate activation to eliminate 2,4-dichlorophenol in the water environment. Experiments and density functional theory calculations uncover reactive sites of the ketonic group displaying the strong site distance effect for the sole active specie of singlet oxygen evolution in the proton-coupled electron transfer regime. Accordingly, the complex water body decontamination has been overwhelmingly realized with the removal efficiency (0.89 (0.007) min−1 for 2,4-dichlorophenol), 3.0–9.4 of pH tolerance, the acceptable stability in continuous-flow and cyclic system. Overall, this work provides novel guidance in metal-free persulfate activation systems for real water remediation.