Low-temperature selective catalytic reduction of NO
x
with NH
3
over Fe–Cu mixed oxide/ZSM-5 catalysts
containing Fe
2
CuO
4
phase
Jie Zhang
•
Hongxia Qu
Received: 11 November 2013 / Accepted: 27 February 2014 / Published online: 23 March 2014
Ó Springer Science+Business Media Dordrecht 2014
Abstract Novel Fe–Cu mixed oxide/ZSM-5 catalysts were prepared for low-
temperature selective catalytic reduction (SCR) of NO
x
with ammonia. Fe–CuO
x
/
ZSM-5 catalysts showed higher activity than FeO
x
/ZSM-5 or CuO
x
/ZSM-5. The
NO
x
conversion with Fe–CuO
x
/ZSM-5 was over 98 % within the temperature range
from 180 to 400 °C. X-ray powder diffraction (XRD) results suggested that a new
crystal phase of Fe
2
CuO
4
appeared in the Fe–CuO
x
/ZSM-5 catalysts. NO-temper-
ature programmed desorption (NO-TPD) showed that more NO was adsorbed onto
the catalyst when the Fe
2
CuO
4
phase appeared. Electron paramagnetic resonance
(EPR) and X-ray photoelectron spectroscopy (XPS) results showed that Fe and Cu
were present in different valence states in the catalysts. EPR results indicated that
Cu
2?
may be a product of a series of reactions which happened when NO and O
2
were added into the Fe–CuO
x
/ZSM-5 catalyst. Intensive analysis of fresh and used
catalysts by XPS revealed that electron transfer between Fe and Cu ions in Fe
2
CuO
4
may play an important role in SCR of NO
x
with ammonia.
Keywords Low temperature Á NH
3
-SCR Á Fe–Cu mixed oxide/ZSM-5 Á
Fe
2
CuO
4
Á Electron transfer
Introduction
NO
x
has done great harm to the environment; it is not only one of the main causes of
acid rain, but also the source of photochemical smog. Moreover, it can damage the
ozone layer, which is vital to human life. The major source of nitrogen oxides is
combustion of fossil fuels, such as coal in electrical power plants or petroleum in
J. Zhang Á H. Qu (&)
School of Chemical Engineering, Nanjing University of Science and Technology,
Nanjing 210094, People’s Republic of China
e-mail: sandykobe@126.com
123
Res Chem Intermed (2015) 41:4961–4975
DOI 10.1007/s11164-014-1580-2
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