INVESTIGADORES
BONELLI Pablo Ricardo
artículos
Título:
Hierarchical, template-free self-assembly morphologies In CeO2 synthesized via urea-hydrothermal method
Autor/es:
ROSARIO SUAREZ ANZORENA; MUÑOZ, FERNANDO F.; PABLO BONELLI; ANA LEA CUKIERMAN; SUSANA LARRONDO
Revista:
CERAMICS INTERNATIONAL
Editorial:
ELSEVIER SCI LTD
Referencias:
Año: 2020 vol. 46 p. 11776 - 11785
ISSN:
0272-8842
Resumen:
Nano-crystalline CeO2 was synthesized via the urea-hydrothermal method without templates orstructure-directing agents. The synthesis parameters Ce3+ to Ce4+ and urea to cation molarratios, reaction temperature and reaction time were varied to analyze their effect onmorphology, texture and reducibility. The analysis of the obtained morphologies providesstrong evidence of a hierarchical and sequential template-free self-assembly process thatevolves from shuttles to dumbbells to spheres. In all cases, the morphology of samples remainsunchanged even after calcination at 500 °C. The presence of Ce4+ in the initial solution clearlyprovides the full self-assembly sequence and is decisive for obtaining non-hollow spheres ofCeO2 with high specific surface area and high pore volume. Besides, if only Ce3+ is present,typical CeOHCO3 shuttle-like particles with orthorhombic structure are obtained. The use ofCe3+ in combination with Ce4+ produces partial sequences of the self-assembly process thatprovide a strong indication of the hierarchical sequence.The urea to cation molar ratio controls the nucleation process and proves to be crucial toobtain the self-assembly sequence. On the other hand, temperature and reaction timeshow a moderate effect on morphology.
