A facile hydrothermal synthesis of 3D flowerlike CeO2via a cerium oxalate precursor

Abstract

In this paper, a simple one-step hydrothermal method has been developed to prepare three-dimensional CeO₂ microflower structures via a cerium oxalate precursor. X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), field-emission scanning electron microscopy (FE-SEM) and thermal gravimetric (TG) analysis were utilized to characterize the products. Herein, unlike the conventional calcination of a cerium oxalate precursor, oxalic acid acted not only as a precipitator but also as a modifier of morphology with a defined amount of C₂O₄²⁻, while hydrogen peroxide (H₂O₂) was introduced as an oxidant to make the full conversion from Ce₂(C₂O₄)₃·10H₂O to CeO₂ in the hydrothermal process with the preserved flowerlike morphology. The as-obtained CeO₂ microflowers displayed a high surface area of 147.6 m² g⁻¹ and narrow pore size of 3.759 nm by N₂ adsorption and desorption measurement, and the H₂-TPR test showed its better reduction behavior. Furthermore, CeO₂ microflowers with hierarchical structures presented a higher catalytic activity for CO oxidation.