Switching the reaction mechanisms and pollutant degradation routes through active center size-dependent Fenton-like catalysis

Rationally regulating reaction mechanisms in Fenton-like reactions by tuning the properties of catalysts is of great significance, but still challenging. Herein, we synthesized various active center size-dependent catalysts to realize the switching of reaction mechanisms and pollutant degradation routes in peroxymonosulfate (PMS) activation systems. The results illustrated that the reaction mechanism transformed from radical oxidation (51.64%) to nonradical oxidation (89.92%) with the decrease of active center size from nanoparticle (CoNP-NC) to single atom (CoSA-NC). The evolution of reactive species switched the degradation intermediates and pathway of sulfisoxazole (SIZ). The generation of singlet oxygen (1O2) in CoSA-NC/PMS tends to selectively attack electron-rich site of SIZ, while reaction between radicals and SIZ prefers non-selective oxidation in CoNP-NC/PMS system. Besides, the toxicity tests indicated that the conversion from non-selective to selective oxidation resulted in lower toxicity of effluent after reaction, which can further reduce environmental risks of effluent.

Automated summary

Rationally regulating reaction mechanisms in Fenton-like reactions by tuning the properties of catalysts is challenging but significant. Various catalysts with different active center sizes were synthesized to realize the switching of reaction mechanisms and pollutant degradation routes in peroxymonosulfate (PMS) activation systems. The transformation of reaction mechanism from radical oxidation to nonradical oxidation was observed with the decrease of active center size. The toxicity tests indicated that the conversion from non-selective to selective oxidation resulted in lower toxicity of effluent after reaction, reducing environmental risks.