Synthesis of Co-doped CeO₂ nanoflower: Enhanced adsorption and degradation performance toward tetracycline in Fenton-like reaction

In Fenton-like reaction, adsorption and degradation are inseparable processes. The pollutants were enriched on the surface of catalyst by adsorption leading to the increase of the local concentration, and this was beneficial for acceleration of the degradation rate. Therefore, a catalyst with high adsorption capacity, low metal leaching and rapid activation rate toward peroxymonosulfate (PMS) was highly desirable. In this paper, Co-doped CeO₂ (Co-CeO₂) nanoflower was prepared via a solvothermal-calcination process. The nanoflower with a hierarchical porous structure was made up of dozens of nanosheets. Compared to CeO₂, more Ce(Ⅲ) sites and defects were generated on Co-CeO₂ surface, and the maximum adsorption capacity was increased by 1.92 times. Benefiting from the high activity of Co toward the activation of PMS, the degradation rate was enhanced 6.7 times. The major radicals were determined and the corresponding degradation mechanism was revealed. Additionally, Co-CeO₂ nanoflower was demonstrated to be high efficient in many persistent organic pollutant degradation and also exhibited outstanding reusability after several cycles. Moreover, the leaching of toxic Co ions was 12 times lower than the referenced Co₃O₄. This work provides a promising approach on rational design a catalyst with high adsorption property and degradation efficiency in Fenton-like reaction for environmental remediation.