Sub-15 nm CeO2 nanowires as an efficient nonnoble metal catalyst in the room-temperature oxidation of aniline
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2018
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Catalysis Science and Technology
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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.
Como referenciar
SILVA, ANDERSON G.M. da; BATALHA, DANIEL C.; RODRIGUES, THENNER S.; CANDIDO, EDUARDO G.; LUZ, SULUSMON C.; FREITAS, ISABEL C. de; FONSECA, FABIO C.; OLIVEIRA, DANIELA C. de; TAYLOR, JASON G.; TORRESI, SUSANA I.C. de; CAMARGO, PEDRO H.C.; FAJARDO, HUMBERTO V. Sub-15 nm CeO2 nanowires as an efficient nonnoble metal catalyst in the room-temperature oxidation of aniline. Catalysis Science and Technology, v. 8, n. 7, p. 1828-1839, 2018. DOI: 10.1039/c7cy02402a. Disponível em: http://repositorio.ipen.br/handle/123456789/29366. Acesso em: 25 Apr 2024.
Esta referência é gerada automaticamente de acordo com as normas do estilo IPEN/SP (ABNT NBR 6023) e recomenda-se uma verificação final e ajustes caso necessário.