Selective catalytic reduction of NOx by NH3 at low temperature over manganese oxide catalysts supported on titanate nanotubes
Por:
Camposeco R., Castillo S., Rodríguez-González V., García-Serrano L.A., Mejía-Centeno I.
Publicada:
1 ene 2018
Ahead of Print:
1 ene 2018
Resumen:
We report the NO conversion with NH3 at low temperature over
MnOx-supported on titanate nanotubes. The effect of SO2 and water on
catalytic activity was also analyzed. For the catalytic activity tests,
three catalysts with 1, 3, and 5wt.% of MnOx were synthesized. A high
NO conversion (92%) at 180 degrees C is reported for the 1Mn/NTiO2
catalyst. The further addition of MnOx to the support improves the
catalytic activity but NO conversion (95%) was shifted to a higher
temperature (from 180 to 220 degrees C). However, the presence of SO2
(50ppm) and water (5 vol.%) diminishes the NO conversion up to 60%,
which remains after 300min. We found that addition of MnOx increases the
Lewis acid sites concentration of the nanotubes. As the Lewis acid sites
increase (from 1.86 to 3.56 mu mol m(-2)), the Mn4+/Mn3+ ratio on the
surface of the nanotubes decreases (from 4 to 1.6), which indicates that
the surface of the catalysts is deficient in electrons. We concluded
that a high Lewis acid sites concentration and a low Mn4+/Mn3+ ratio,
hence a surface deficient in electrons, improves the catalytic activity
to remove NO on the Mn/NTiO2 catalysts.
Filiaciones:
Instituto de Ciencias Aplicadas y Tecnología, Universidad Nacional Autónoma de México, Circuito Exterior S/N C.U., Mexico City, México
Dirección de Investigación en Transformación de Hidrocarburos, Instituto Mexicano del Petróleo, Mexico City, México
División de Materiales Avanzados, Instituto Potosino de Investigación Científica y Tecnológica, San Luis Potosí, S.L.P., México
Centro Interdisciplinario de Investigaciones y Estudios sobre Medio Ambiente y Desarrollo, Instituto Politécnico Nacional, Mexico City, México
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