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Investigations on the Antimony Promotional Effect on CeO 2 –WO 3 /TiO 2 for Selective Catalytic Reduction of NO x with NH 3
Author(s) -
Yan Lijun,
Liu Yangyang,
Hu Hang,
Li Hongrui,
Shi Liyi,
Zhang Dengsong
Publication year - 2016
Publication title -
chemcatchem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.497
H-Index - 106
eISSN - 1867-3899
pISSN - 1867-3880
DOI - 10.1002/cctc.201600332
Subject(s) - catalysis , antimony , inorganic chemistry , selective catalytic reduction , ammonia , doping , chemistry , ammonia production , diffuse reflectance infrared fourier transform , materials science , photocatalysis , organic chemistry , optoelectronics
Antimony‐doped CeO 2 –WO 3 /TiO 2 catalysts were prepared by a conventional ultrasonic‐assisted impregnation method and employed for selective catalytic reduction of NO x with NH 3 at low temperature. Both experimental work and theoretical studies were employed to elucidate the effect of the antimony on promoting the CeO 2 –WO 3 /TiO 2 catalyst. The catalytic activity of CeO 2 –WO 3 /TiO 2 was largely improved after the addition of antimony oxide. It was found that antimony doping reduced the crystal size and strengthened the synergistic effect between the metal cations, which resulted in a favorable catalyst surface status with abundant active surface oxygen, Brønsted acid sites, and effective electron transfer. Both in situ diffuse reflectance infrared Fourier transform analysis and DFT calculation results revealed that the ammonia and NO x desorption behavior over the catalyst surface were considerably different. For the ammonia species, rather large amounts of the active NH 4 + and NH 3 species anchored on the surface of the Sb‐doped CeO 2 –WO 3 /TiO 2 . In view of the NO x species, the amount of nonactive bidentate nitrate species was largely reduced and the amount of active gaseous NO 2 species was clearly enhanced, which lowered the activation energy of the catalytic process and gave rise to the elevated low‐temperature NH 3 selective catalytic reduction activity. All these preferable properties resulted in the elevated de‐NO x activity of the Sb‐doped CeO 2 –WO 3 /TiO 2 catalyst.