Cerium-based porous coordination polymers with hierarchical superstructures: fabrication, formation mechanism and their thermal conversion to hierarchical CeO2Electronic supplementary information (ESI) available: Additional graphs. See DOI: 10.1039/c5qi00016e

• Main Authors: Zhao, Yong-Xia, Nie, Zhi-Wen, Shi, Meng-Meng, Zeng, Cheng-Hui, Li, Yuan, Wang, Lei, Zhong, Sheng-Liang
• Format: Journal Article
• Language: English
• Published: 02.06.2015
• ISSN: 2052-1553
• DOI: 10.1039/c5qi00016e

In this work, cerium-based porous coordination polymers (Ce-CPs) with hierarchical superstructures have been successfully synthesized on a large scale employing cerium nitrate as the metal salt and 2,5-pyridinedicarboxylic acid (2,5-H 2 pdc) as the ligand by a mixed-solvothermal route. The as-obtained products were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), thermogravimetry and differential thermal analysis (TG-DTA). It was found that the hierarchical superstructures are composed of asymmetric branches with lengths ranging from 10 to 50 μm. The reaction parameters such as reaction temperature, total concentrations of the reactants, solvent composition, and the reaction time were investigated systematically. A possible formation mechanism for the hierarchical superstructures has been proposed to interpret the growth process. CeO 2 with similar hierarchical structures could be obtained after thermolysis of the Ce-CP precursors at 450 °C for 4 h. The UV-vis adsorption spectrum of the obtained CeO 2 shows that the band gap energy ( E g ) is 2.64 eV, which is lower than that of bulk ceria. Moreover, the as-obtained CeO 2 also exhibited remarkable ability to remove rhodamine B (RhB). Novel three-dimensional (3D) ceria hierarchical structures have been prepared via a thermolysis of the corresponding porous coordination polymer precursors.