Alkali metals as promoters in Co–Mn–Al mixed oxide for N2O decomposition

Authors:  L. Obalová, K. Karásková, A. Wach, P. Kustrowski, K. Mamulová-Kutláková, S. Michalik, K. Jirátová

Abstract:
Alkali promoted Co₄MnAlO_x mixed oxide (molar ratio of alkali metal/Co = 0.037) were prepared by impregnation of calcined Co–Mn–Al hydrotalcite (molar ratio Co:Mn:Al = 4:1:1) with an aqueous solution of Li, Na, K, Rb or Cs nitrate. The catalysts were characterized by AAS, SEM/EDX, N₂ physisorption, XRPD, XPS, H₂-TPR, TPD of CO₂ and NH₃ and tested for N₂O decomposition in inert gas and simulated waste gas from HNO₃ production. N₂O conversion over alkali promoted Co₄MnAlO_x mixed oxide decreased in order Cs > Rb >K> Na = Co₄MnAlO_x > Li in inert gas and was shifted to the lower values in the presence of typical components (NOx, O₂ and H₂O) of flue gas. The addition of alkali promoters to the Co₄MnAlOx mixed oxide resulted in a modification of both electronic properties of active metals and acid–base function of the catalyst surface. The promotional effect of alkali metals is connected with their ionization potential, the charge transfer to the catalyst and a decrease in binding energies of all catalyst components (Co, Mn, Al and O). Pilot plant verification of N₂O decomposition over K-promoted Co4MnAlOx is shown.

Keywords:
N₂O decomposition
Alkali metal
Promoter
Cobalt oxide
Layered double hydroxide

Published in: Applied catalysis A: General  (Volumes 462–463, Pages 1-310, 10 July 2013)

Publisher: Elsevier      

ISSN Information: 0926-860X

Alkali metals as promoters in Co–Mn–Al mixed oxide for N2O decomposition

Bình luận của bạn

*

*

*

*

 Captcha

Gửi bình luận nhập lại