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Effects of Transition‐Metal Substitution on the Catalytic Properties of Barium Hexaaluminogallate
Author(s) -
Yamaguchi Toshiaki,
Sakamoto Wataru,
Yogo Toshinobu,
Hirano Shinichi
Publication year - 2002
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.2002.tb00191.x
Subject(s) - catalysis , transition metal , barium , coprecipitation , inorganic chemistry , chemistry , metal , space velocity , selective catalytic reduction , barium carbonate , materials science , selectivity , organic chemistry , raw material
The effects of the substitution of transition‐metal ions and/or reductant gases on the catalytic properties of barium hexaaluminogallate were investigated. Transition‐metal‐substituted hexaaluminogallates (BaM(Al,Ga) 11 O 19 , M = transition metal, Al/Ga = 9/3) were synthesized from aqueous metal nitrates and ammonium carbonate by the coprecipitation followed by crystallization at 1100°C. The direct NO x reduction was observed over BaM(Al,Ga) 11 O 19 to be around 10%. The NO x removal activity of BaM(Al,Ga) 11 O 19 powders was improved by addition of C 3 H 6 as a reductant gas. Co‐, Ni‐ and Cu‐substituted BaM(Al,Ga) 11 O 19 catalysts exhibited about 40% NO x reduction with C 3 H 6 in excess oxygen at a high space velocity of 10 000 h −1 . The NO x reduction on Mn‐ and Fe‐substituted BaM(Al,Ga) 11 O 19 catalysts was less than 10% even in the presence of C 3 H 6 . The temperature of the effective NO x reduction on BaM(Al,Ga) 11 O 19 catalysts could be adjusted from 350° to 500°C by the selection of the transition‐metal substitution in the catalysts. The catalysts hold high activities for NO x reduction even at 500°C in water vapor produced in the combustion system of reductant gases.