Please use this identifier to cite or link to this item: http://www.repositorio.ufop.br/handle/123456789/10355
Title: Sub-15 nm CeO2 nanowires as an efficient nonnoble metal catalyst in the room-temperature oxidation of aniline.
Authors: Silva, Anderson Gabriel Marques da
Batalha, Daniel Carreira
Rodrigues, Thenner Silva
Candido, Eduardo Guimarães
Luz, Sulusmon Cesar
Freitas, Isabel Cristina de
Fonseca, Fabio Coral
Oliveira, Daniela Coelho de
Taylor, Jason Guy
Torresi, Susana Ines Cordoba de
Camargo, Pedro Henrique Cury
Fajardo, Humberto Vieira
Issue Date: 2018
Citation: SILVA, A. G. M. da. et al. Sub-15 nm CeO2 nanowires as an efficient nonnoble metal catalyst in the room-temperature oxidation of aniline. Catalysis Science & Technology, v. 8, n. 7, p. 1828-1839, fev. 2018. Disponível em: <http://pubs.rsc.org/en/content/articlepdf/2018/cy/c7cy02402a>. Acesso em: 05 abr. 2018
Abstract: We described herein the facile synthesis of sub-15 nm CeO2 nanowires based on a hydrothermal method without the use of any capping/stabilizing agent, in which an oriented attachment mechanism took place during the CeO2 nanowire formation. The synthesis of sub-15 nm CeO2 nanowires could be achieved on relatively large scales (∼2.6 grams of nanowires per batch), in high yields (>94%), and at low cost. To date, there are only a limited number of successful attempts towards the synthesis of CeO2 nanowires with such small diameters, and the reported protocols are typically limited to low amounts. The nanowires displayed uniform shapes and sizes, high surface areas, an increased number of oxygen defects sites, and a high proportion of Ce3+/Ce4+ surface species. These features make them promising candidates for oxidation reactions. To this end, we employed the selective oxidation of aniline as a model transformation. The sub-15 nm CeO2 nanowires catalyzed the selective synthesis of nitrosobenzene (up to 98% selectivity) from aniline at room temperature using H2O2 as the oxidant. The effect of solvent and temperature during the catalytic reaction was investigated. We found that such parameters played an important role in the control of the selectivity. The improved catalytic activities observed for the sub-15 nm nanowires could be explained by: i) the uniform morphology with a typical dimension of 11 ± 2 nm in width, which provides higher specific surface areas relative to those of conventional catalysts; ii) the significant concentration of oxygen vacancies and high proportion of Ce3+/Ce4+ species at the surface that represent highly active sites towards oxidation reactions; iii) the crystal growth along the (110) highly catalytically active crystallographic directions, and iv) the mesoporous surface which is easily accessible by liquid substrates. The results reported herein demonstrated high activities under ambient conditions, provided novel insights into selectivities, and may inspire novel metal oxide-based catalysts with desired performances
URI: http://www.repositorio.ufop.br/handle/123456789/10355
metadata.dc.identifier.uri2: https://pubs.rsc.org/en/content/articlepdf/2018/cy/c7cy02402a
ISSN: 20444761
Appears in Collections:DEQUI - Artigos publicados em periódicos

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