Cerium dioxide has a comparatively lower Ce4+/Ce3+ redox pair, which leaves abundant oxygen vacancies on oxide lattice, also making incorporation of foreign ion and subsequent applications feasible and convenient. In this work, a series of cerium–yttrium mixed oxides were prepared by using polyvinylpyrrolidone as major template through sol–gel, which were further employed as catalyst for dehydration of aniline with formic acid into N-phenylformamide. Characterizations reveal that synthetic samples have a variety of morphologies including nanoparticle, microflower, and uniform microrods. The monitoring of particle size, zeta potential, and ultraviolet-visible (UV–Vis) of preparative solution indicate that self-assembly of polyvinylpyrrolidone and its subsequent reaction with metal ion determines sample morphology. In catalytic dehydration, all samples show high dehydration efficiencies that are comparable to those from anhydrous Na2SO4 and combination of dicyclohexylcarbodiimide with 4-dimethylaminopyridine and dichloromethane shows better outputs than water. In association with structural analysis, cerium looks more active than yttrium, while yttrium mainly plays as a structure-directing and pore-forming agent. This study may contribute to micro-/nanofabrication of rare earth composites and their catalytic applications.

中文翻译：

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铈-钇二元氧化物微花：合成、表征和催化脱水性能

二氧化铈具有相对较低的Ce4+/Ce3+氧化还原对，在氧化物晶格上留下丰富的氧空位，也使得外来离子的掺入和后续应用变得可行和方便。在这项工作中，以聚乙烯吡咯烷酮为主要模板，通过溶胶-凝胶制备了一系列铈-钇混合氧化物，它们进一步用作苯胺与甲酸脱水成N-苯基甲酰胺的催化剂。表征表明合成样品具有多种形态，包括纳米颗粒、微花和均匀的微棒。对制备溶液的粒径、zeta 电位和紫外-可见 (UV-Vis) 的监测表明，聚乙烯吡咯烷酮的自组装及其随后与金属离子的反应决定了样品形态。在催化脱水中，所有样品都显示出与无水 Na2SO4 相媲美的高脱水效率，并且二环己基碳二亚胺与 4-二甲氨基吡啶和二氯甲烷的组合显示出比水更好的输出。与结构分析相关，铈看起来比钇更活跃，而钇主要用作结构导向和成孔剂。该研究可能有助于稀土复合材料的微/纳米制造及其催化应用。而钇主要起结构导向和成孔剂的作用。该研究可能有助于稀土复合材料的微/纳米制造及其催化应用。而钇主要起结构导向和成孔剂的作用。该研究可能有助于稀土复合材料的微/纳米制造及其催化应用。