Dual Nonradical Catalytic Pathways Mediated by Nanodiamond-Derived sp2/sp3 Hybrids for Sustainable Peracetic Acid Activation and Water Decontamination

Peracetic acid (PAA) oxidation catalyzed by metal-free carbons is promising for advanced water decontamination. Nevertheless, developing reaction-oriented and high-performance carbocatalysts has been limited by the ambiguous understanding of the intrinsic relationship between carbon chemical/molecular structure and PAA transformation behavior. Herein, we comprehensively investigated the PAA activation using a family of well-defined sp 2 /sp 3 carbon hybrids from annealed nanodiamonds (ANDs). The activity of ANDs displays a volcano-type trend, with respect to the sp 2 /sp 3 ratio. Intriguingly, sp 3 -C-enriched AND exhibits the best catalytic activity for PAA activation and phenolic oxidation, which is different from persulfate chemistry in which the sp 2 network normally outperforms sp 3 hybridization. At the electron-rich sp 2 -C site, PAA undergoes a reduction reaction to generate a reactive complex (AND-PAA*) and induces an electron-transfer oxidation pathway. At the sp 3 -C site adjacent to C═O, PAA is oxidized to surface-confined OH* and O* successively, which ultimately evolves into singlet oxygen ( 1 O 2 ) as the primary reactive species. Benefiting from the dual nonradical regimes on sp 2 /sp 3 hybrids, AND mediates a sustainable redox recycle with PAA to continuously generate reactive species to attack water contaminants, meanwhile maintaining structural/chemical integrity and exceptional reusability in cyclic runs.