Coordination-Assisted Synthesis of Nanoheterojunctions with Asymmetric Interfacial Oxygen Vacancies for Nonradical Persulfate Activation

Programming the location and coordination environment of oxygen vacancies in metal oxides remains a central synthetic challenge. Here, we report a coordination-assisted synthesis that converts an amorphous coordination polymer precursor, prepared by grinding cobalt and zinc nitrates with 2-methylimidazole in near-complete solid recovery, into oxide nanoparticles (∼10 nm) upon mild calcination. The Zn/Co ratio serves as a compositional switch that selects among pure Co3O4, Zn-doped Co3O4, and ZnO/Co3O4 nanoheterojunctions. The heterojunction interface stabilizes abundant asymmetric interfacial oxygen vacancies (formation energy 1.06 versus 3.27 eV for the doped lattice), which mediate nonradical peroxydisulfate activation through surface-complex formation and direct electron transfer, oxidatively polymerizing bisphenol A into insoluble deposits and achieving its complete removal within 9 min over a broad pH range. Compositional preorganization via amorphous coordination intermediates thus emerges as a general and scalable principle for interface and defect engineering in mixed-metal oxides.