Interfacial Oxygen Vacancy-Metal Dual-Sites on Co-CoO-Co₃O₄/CN for Highly Efficient Fenton-like Reactions

Designing advanced cobalt-based catalysts capable of selectively generating singlet oxygen (¹O₂) is crucial for suppressing interference from coexisting reactive oxygen species in peroxymonosulfate (PMS) activation and achieving efficient degradation of organic pollutants. In this work, an interface engineering strategy was employed to fabricate Co-CoO-Co₃O₄/CN featuring abundant oxygen vacancies and Co active sites. The constructed Co-CoO-Co₃O₄/CN + PMS system achieves nearly complete degradation of 50 mg·L^-1 RhB within 20 min, and its catalytic activity outperforms most reported cobalt-based catalysts, with a specific rate constant value as high as 11.23 L²·min^-1·g^-2. In addition, the Co-CoO-Co₃O₄/CN + PMS system exhibits excellent broad-spectrum applicability, outstanding environmental tolerance, and stability. It enables continuous treatment of 49.8 L of RhB solution, with the degradation efficiency consistently maintained above 99%. Systematic investigations demonstrate that Co-CoO-Co₃O₄/CN exhibits a strong interaction with PMS, and this enhanced interaction can drive the efficient conversion of PMS into superoxide anion radicals (O₂^•-), which are further transformed into ¹O₂. This work provides new insights into the rational design of high-performance cobalt-based catalysts, and paves the way for efficient PMS activation and selective ¹O₂ generation.