Defect generation and morphology transformation mechanism of CeO2 particles prepared by molten salt method
Defect generation and morphology transformation mechanism of CeO2 particles prepared by molten salt method
复制标题
熔盐法制备CeO2颗粒的缺陷产生及形貌转变机制
DOI：
10.1016/j.ceramint.2022.10.007
复制
发表时间：
2022-12-16
影响因子：
5.2
通讯作者：
Pu，Yongping
中科院分区：
文献类型：
--
作者：
Ma，Jiahui;Xu，Ning;Pu，Yongping
CeO2以其独特的化学性质在工业领域得到了广泛的应用。本工作采用一种简单的熔盐法制备了一系列形貌、尺寸和缺陷浓度可控的CeO2颗粒。温度和熔盐浓度的调节对最终产物的形貌和粒径有较大影响，而延长保温时间影响不大。采用离子掺杂和还原气氛焙烧的方法调节缺陷浓度，以提高CeO2的化学活性。扫描电子显微镜结果表明，在两种处理方式下，CeO2颗粒的形貌均由球形转变为八面体。Rietveld精细化结果和XPS谱表明，提高焙烧温度、减少气氛焙烧和离子掺杂有利于提高CeO2样品的氧空位和Ce3+浓度，这是提高样品光催化活性的原因。此外，CeO_2前驱体分解形成的晶体的定向附着、团聚和合并是CeO_2颗粒生长的关键。具有暴露的低能面的聚集体直接合并形成各种形态的粒子，以保持其自身的低能量。
Ceria is widely used in industrial fields due to its unique chemical properties. In this work, a series of CeO2particles with controllable morphology, size, and defect concentration were obtained by a simple molten salt method. The adjustment of temperature and molten salt concentration has a considerable effect on the morphology and particle size of the final CeO2particles while prolonging the holding time has little effect. Ion doping and reducing atmosphere calcination were used to regulate the defect concentration to improve the chemical activity of CeO2particles. SEM results show that the morphology of CeO2particles transforms from sphere to octahedron under the two treatments. The Rietveld refinement results and the XPS spectra indicate that increasing calcination temperature, reducing atmosphere calcination and ion doping are beneficial to improving the oxygen vacancies and Ce3+concentration of CeO2samples, which are the reason for enhancing the photocatalytic activity of the samples. Moreover, the oriented attachment, agglomeration and merging of crystals formed by the decomposition of cerium precursors are the key to the growth of CeO2particles. Aggregates with exposed low-energy planes merge directly to form particles of various morphologies to maintain their own low energy.