Regulation of electronic structures of MOF-derived carbon via ligand adjustment for enhanced Fenton-like reactions

Peroxymonosulfate (PMS)-based Fenton-like reactions are widely used for wastewater remediation. Metal-free carbonaceous activators can avoid the secondary pollution caused by metal leaching but often suffer from insufficient activity due to limited active centers and mass transfer barriers. Here, we prepared a series of heteroatom (N, S, F)-doped, highly porous carbonaceous materials (UC-X, X = N, S, F) by pyrolyzing UiO-66 precursors assembled by various organic ligands. Density functional theory calculations showed that the heteroatoms modulated the electronic structures of the carbon plane. UC-X exhibited significantly enhanced PMS activation capability compared with the undoped counterpart, in the efficiency order of UC-N > UC-S > UC-F > UC. UC-N (calcined at 1000 degrees C) showed the best PMS activation, exceeding that of commonly used carbocatalysts. The prominent performance of UC-N originated from its unique porous structure and homogeneously dispersed graphitic N moieties. Trapping experiments and electron spin resonance showed a nonradical degradation pathway in the UC-N/PMS system, through which organics were oxidized by donating electrons to UC-N/PMS* metastable complexes. This work not only reports a universal way to access high-performance, metal-free PMS activators but also provides insight into the underlying mechanism of the carbon-activated PMS process. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

The study demonstrates that porous carbon materials doped with heteroatoms can significantly enhance the activation capability of PMS, providing a universal and high-performance approach for metal-free wastewater treatment.