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Preparation of γ ‐Fe 2 O 3 Catalysts and their deNO x Performance: Effects of Precipitation Conditions
Author(s) -
Wang Dong,
Yang Qilei,
Li Xiansheng,
Peng Yue,
Li Bing,
Si Wenzhe,
Lu Chunmei,
Gan Lina
Publication year - 2018
Publication title -
chemical engineering and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.403
H-Index - 81
eISSN - 1521-4125
pISSN - 0930-7516
DOI - 10.1002/ceat.201600488
Subject(s) - coprecipitation , catalysis , titration , chemistry , crystallization , selective catalytic reduction , precipitation , crystal structure , inorganic chemistry , oxygen , analytical chemistry (journal) , nuclear chemistry , crystallography , chromatography , biochemistry , physics , organic chemistry , meteorology
Magnetic γ ‐Fe 2 O 3 catalysts were prepared by microwave‐assisted coprecipitation utilizing the direct‐titrate and back‐titrate precipitation technique with different precipitants, namely, (NH 4 ) 2 CO 3 , NaOH, Na 2 CO 3 , and NH 4 OH, which were evaluated in the selective catalytic reduction of NO x with NH 3 . The optimum γ ‐Fe 2 O 3 catalyst preparation method was direct titration with NH 4 OH as the precipitant, which exhibits high deNO x efficiency. This direct titration was effective to maintain the proper crystallization degree of γ ‐Fe 2 O 3 , improve the pore structure, and suppress the formation of α ‐Fe 2 O 3 phase, being advantageous to get tiny and uniform discrete γ ‐Fe 2 O 3 particles with high activity in selective catalytic reduction. NH 4 + ‐based precipitants in direct titration leads to an increase of the surface O/Fe atom ratio, and more lattice oxygen sites are exposed to the crystal surface.