Selective catalytic reduction of nitrogen oxides by ammonia over Co3O4 nanocrystals with different shapes

Authors: Bo Meng, Zongbin Zhao, Xuzhen Wang, Jingjing Liang, Jieshan Qiu

Abstract:
In this work, single-crystalline one-dimensional Co₃O₄ nanorods with well-defined crystal planes as catalysts in the selective catalytic reduction of NO by ammonia are investigated. The Co₃O₄nanorods synthesized by ethylene glycol-mediated precipitation at 160^◦C predominantly expose {1 1 0} planes which are rich in Co³⁺ species, while the traditional Co₃O₄ nanoparticles expose the {0 0 1} and {1 1 1} planes which contain mainly Co2+ species. Compared with Co₃O₄ nanoparticles, Co₃O₄nanorods show much higher NO_x conversion in NH₃-SCR reaction. TPD of various reactant gases, including NH₃, NO, NO/NH₃, NO/O₂, NO/NH₃/O₂, and transient experiment reveals Co₃O₄ nanorods adsorb a large amount of ammonia on their surface. Slight surface H₂ reduction significantly decreases the activity of Co₃O₄ nanocrystals, while O₂ re-oxidation partially recovers their catalytic activity, demonstrating the presence of Co³⁺ cations on the surface of Co₃O₄ nanocatalysts actually acts as the active sites in NH₃-SCR reaction. The present results indicate that novel catalyst with high activity can be designed by morphology control at nanoscale.

Keywords:
Co₃O₄ nanorods
NO_x reduction
Catalyst morphology
Catalytic activity

Published in: Applied catalysis B: Environmental  (Volume 129, Pages 1-614, 17 January 2013)

Publisher: Elsevier  

ISSN Information: 0926-3373

Selective catalytic reduction of nitrogen oxides by ammonia over Co3O4 nanocrystals with different shapes

Bình luận của bạn

*

*

*

*

 Captcha

Gửi bình luận nhập lại