Exhaust gas purging composition
AssigneeMitsui Mining & Smelting Co., Ltd.
InventorsMichitaka Yamaguchi, Satoshi Watanabe
Life of this patent
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Abstract
A composition for exhaust gas purification containing Y—Mn—O and Al2O3 and having a specific surface area (SSA) retention satisfying inequality (1) SSA retention (%) >−61.54×(Y—Mn—O ratio)+75.55 and inequality (2) SSA retention (%) >45 (2), where SSA retention is represented by (SSA after aging)/(initial SSA)×100 (%). The SSA after aging and the initial SSA are as defined in the description. The Y—Mn—O ratio is a mass ratio of Y—Mn—O to the sum of Y—Mn—O and Al2O3 in the composition for exhaust gas purification, being represented by Y—Mn—O/(Y—Mn—O+Al2O3).
Claims5
A composition for exhaust gas purification comprising an yttrium-manganese composite oxide and Al2O3 and having a specific surface area (SSA) retention satisfying inequalities (1) and (2):
- SSA retention (%)>−61.54×(Y—Mn—O ratio)+75.55 (1)
- SSA retention (%)>45 (2)
- wherein SSA retention is represented by (SSA after aging)/(initial SSA)×100 (%);
- initial SSA is the SSA (m2/g) of a composition for exhaust gas purification having been subjected to a heat treatment at 500° C. for 1 hour followed by no further heat treatment;
- SSA after aging is the SSA (m2/g) of the composition for exhaust gas purification having been subjected to a heat treatment at 500° C. for 1 hour followed by another heat treatment at 980° C. for 25 hours;
- Y—Mn—O represents the yttrium-manganese composite oxide;
- and Y—Mn—O ratio is a mass ratio of the Y—Mn—O to the sum of the Y—Mn—O and Al2O3 in the composition for exhaust gas purification, being represented by Y—Mn—O/(Y—Mn—O+Al2O3).
Dependencies are inferred from the claim text.