In-situ regulation of Cu single-atom sites with axial nanoclusters in MOFs for selective fenton-like reactions in water decontamination

Single-atom catalysts (SACs) have garnered significant attention owing to their high reactivity; however, precise control of their electronic structure for Fenton-like process remains a challenge. In this study, we develop a novel technique for regulating the electronic environment of Cu-SACs to activate peroxymonosulfate (PMS) for highly effective degradation of emerging organic pollutants in water. By in-situ axial modification of Cu-SACs with Cu 2 O nanoclusters within a porphyrin metal–organic framework (Cu 2 O clu -Cu SA /PMOF), we finely tuned the electronic structure of Cu-SACs, leading to the selective generation of singlet oxygen ( 1 O 2 ) as the predominant reactive species in a nonradical Fenton-like process. The rate constant of the Cu 2 O clu -Cu SA /PMOF catalyst for PMS oxidation of sulfamethoxazole (SMX) surpassed that of Cu 2 O and Cu SA /PMOF by 12.9 and 3.7 times, respectively, outperforming most state-of-the-art heterogeneous catalysts for PMS activation. Density functional theory calculations elucidated that the modulation of electronic structure of the Cu sites in Cu 2 O clu -Cu SA /PMOF led to the preferred adsorption of PMS in the terminal-O mode and altered the electron transfer from PMS to the Cu sites for 1 O 2 generation through the self-reaction of SO 5 •− intermediates. This work presents a new material strategy by modulating the functionality of single-atoms via axial incorporation of nanoclusters in MOFs, realizing a highly efficient and selective Fenton-like oxidation process for sustainable water purification.