Popkov V I, Tolstoy V P, Nevedomskiy V N
Institute of Chemistry, Saint Petersburg State University, 26 Universitetskii Prospect, Petergof, St. Petersburg, 198504, Russian Federation.
Ioffe Institute, 26 Politekhnicheskaya Street, St. Petersburg, 194021, Russian Federation.
Heliyon. 2019 Mar 28;5(3):e01443. doi: 10.1016/j.heliyon.2019.e01443. eCollection 2019 Mar.
An ultrafine α-CeO-α-FeO nanocomposite was prepared from the ultradispersed nanoparticles of cerium (IV) and iron (III) amorphous hydroxides heat-treated at 600 °С and 900 °С in the air. The initial composites were obtained by the successive ionic layer deposition (SILD) method. According to scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and powder X-ray diffraction (PXRD), the cerium/iron ratio in the synthesized nanocomposite is close to 1:2, and the α-CeO and α-FeO nanocrystals are isometrically shaped and have an average size of 4 ± 1 and 7 ± 1 nm (600 °С) and 24 ± 2 and 35 ± 3 nm (900 °С), respectively. Transmission electron microscopy (TEM) and selected area electron diffraction (SAED) have shown that nanocrystals are evenly distributed in the composite volume and are spatially conjugated. The formation mechanisms of both initial amorphous composites of cerium (IV) and iron (III) hydroxides and of α-CeO and α-FeO nanocrystals were established. It was shown that synthesis of the initial hydroxide composite using the SILD method proceeds via the formation of amorphous cerium hydroxo-peroxide (CeO(OOH)). As a result of the study, a schematic mechanism for the formation of a composite based on ultrafine nanocrystals of cerium (IV) and iron (III) oxides has been proposed.
通过在空气中对铈（IV）和铁（III）非晶态氢氧化物的超分散纳米颗粒在600℃和900℃下进行热处理，制备了一种超细α-CeO-α-FeO纳米复合材料。初始复合材料通过连续离子层沉积（SILD）法获得。根据扫描电子显微镜（SEM）、能量色散X射线光谱（EDX）和粉末X射线衍射（PXRD），合成的纳米复合材料中铈/铁比接近1:2，α-CeO和α-FeO纳米晶体呈等轴形状，平均尺寸分别为4±1和7±1nm（600℃）以及24±2和35±3nm（900℃）。透射电子显微镜（TEM）和选区电子衍射（SAED）表明，纳米晶体均匀分布在复合材料体积中且在空间上共轭。确定了铈（IV）和铁（III）氢氧化物的初始非晶态复合材料以及α-CeO和α-FeO纳米晶体的形成机制。结果表明，使用SILD法合成初始氢氧化物复合材料是通过形成非晶态氢氧化铈过氧化物（CeO（OOH））进行的。作为研究结果，提出了基于铈（IV）和铁（III）氧化物超细纳米晶体形成复合材料的示意机制。
