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Background As an alternative to homogenous metal-catalyst for peroxymonosulfate activation, heterogeneous hybrid catalysts such as metal-doped graphene catalysts are highly desired due to their remarkable catalytic performance and ease of recovery. Method In this work, ultrafine Co3O4 confined in graphene macroscopic microspheres (Co3O4@rGO) were fabricated via coordination-driven interfacial self-assembly, followed by annealing in air. A series of characterizations and experiments verified that this kind of conductive and adsorptive graphitic structure facilitated the elimination of pollutants via a synergistic “adsorption-driven-catalysis’’ process. Significant findings Therefore, almost 100% tetracycline (TC, 0.271 min−1) was eliminated after 30 min, which was far higher than those of reported catalysts. Besides, X-ray photoelectron spectroscopy (XPS) analysis, electron paramagnetic resonance (EPR), and quenching experiments demonstrated that confined cobalt species and oxygen vacancies as highly exposed active sites. The reactive oxygen species (ROS) follow a contribution order: SO4·− ˃ 1O2 ˃ O2·− ˃ ·OH More significantly, a fluidized-column catalytic unit enabled almost zero discharge of TC in continuous sewage treatment system. Overall, this work provided a generally applicable approach to fabricate removable and highly efficient heterogeneous catalysts for environmental remediation. |
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