This work attempts to gain information about the role of trivalent and tetravalent dopants on the structural and catalytic properties of ceria (CeO 2 ). In this study, we have prepared Zr 4+ , La 3+ , and Eu 3+ doped ceria (CZ, CL, and CE) by coprecipitation method and calcined at 773 K. The physicochemical characterization was achieved by using various techniques, namely, X-ray powder diffraction (XRD), Brunauer-EmmettTeller (BET) surface area, high resolution transmission electron microscopy (HRTEM), Raman spectroscopy, temperature programmed reduction (TPR), X-ray photoelectron spectroscopy (XPS), and electron spin resonance (ESR) spectroscopy. The catalytic efficiency for soot oxidation was evaluated by thermogravimetric (TG) method and compared with undoped CeO 2 . Doped CeO 2 catalysts decreased the soot oxidation temperature by more than 158 K compared to pure ceria. This is ascribed to mutual interaction and synergistic effect between the dopant species and the ceria. Among the synthesized nanocatalysts, the CE sample exhibited better performance. The observed better activity of CE was attributed to the presence of more number of oxygen vacancies, a high specific surface area, and easy reducibility as confirmed from Raman, BET surface area, and TPR measurements, respectively.

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The synthesis, X-ray structure and properties of a pentanuclear cobalt(III) coordination cluster [{L (O 2 CCH 3 )Co 2 O(OCH 3 ) 2 } 2 Co](ClO 4 ) 3 (1) (L − = 2,6-bis((3-aminopropylimino)methyl)-4-methylphenolate) are described. The dinucleating L − is coordinated with two cobalt(III) centers to form the {L(O 2 CCH 3 )Co 2 O(OCH 3 ) 2 } unit, where each metal center is in a distorted octahedral N 2 O 4 environment. The oxo and the methoxo ligands of these two dinuclear units assemble a distorted octahedral O 6 coordination sphere around the central cobalt(III). Elemental analysis and spectroscopic (IR, NMR, UV-vis, and HRMS) features are consistent with the pentanuclear structure of the complex. The diamagnetic complex is a 1 : 3 electrolyte in solution. It is redox-active and displays a metalcentered reduction at E 1/2 = −0.04 V (vs. Ag/AgCl).