Exhaust gas treating catalyst and exhaust gas purification apparatus using the same
AssigneeMitsubishi Heavy Industries, Ltd.
InventorsMasatoshi Katsuki, Shuuji Fujii, Atsushi Ueda, Yusuke Yamada
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Abstract
An exhaust gas treating catalyst further improved in denitrification performance is provided. It is an exhaust gas treating catalyst containing a complex oxide represented by the general formula ABO3, where the A-site is composed of a lanthanoid (La) and barium (Ba), and the B-site is composed of iron (Fe), niobium (Nb) and palladium (Pd).
Claims9
An exhaust gas purification apparatus for reducing nitrogen oxides in an exhaust gas to purify the exhaust gas, comprising:
- trapping means for trapping particulate matter in the exhaust gas;
- and
- an exhaust gas treating catalyst for reducing nitrogen oxides in an exhaust gas to purify the exhaust gas, the exhaust gas treating catalyst containing a complex oxide represented by a general formula ABO3, where
- the A-site is composed of a lanthanoid (La) and barium (Ba),
- the B-site is composed of iron (Fe), niobium (Nb) and palladium (Pd), and
- fulfills {LaxBa(1-x)}{FeyNb(1-y)}(1-z)PdzO3,
- where x is in a range of more than 0.30, but 0.95 or less, y is in a range of 0.07 or more, but 0.94 or less, and z is in a range of 0.01 or more, but 0.10 or less, and
- the complex oxide has such a structure that the barium functions as a NOx storing agent, and the niobium act on the palladium to accelerate NO oxidation and NOx reduction,
- the exhaust gas treating catalyst being disposed downstream of the trapping means in a flow-through direction of the exhaust gas.
An exhaust gas purification apparatus for reducing nitrogen oxides in an exhaust gas to purify the exhaust gas, comprising:
- trapping means for trapping particulate matter in the exhaust gas;
- and
- an exhaust gas treating catalyst for reducing nitrogen oxides in an exhaust gas to purify the exhaust gas, the exhaust gas treating catalyst containing a complex oxide represented by a general formula ABO3, where
- the A-site is composed of a lanthanoid (La) and barium (Ba),
- the B-site is composed of iron (Fe), niobium (Nb) and palladium (Pd),
- further containing at least one additional precious metal (PM2) comprising Pt, Rh Ir and Ru, other than palladium (Pd), and
- fulfills PM2/−{LaxBa(1-x)}{FeyNb(1-y)}(1-z)PdzO3,
- where x is in a range of more than 0.30, but 0.95 or less, y is in a range of 0.07 or more, but 0.94 or less, and z is in a range of 0.01 or more, but 0.10 or less, and
- the complex oxide has such a structure that the barium functions as a NOx storing agent, and the niobium act on the palladium to accelerate NO oxidation and NOx reduction,
- the exhaust gas treating catalyst being disposed downstream of the trapping means in a flow-through direction of the exhaust gas.
An exhaust gas purification apparatus for reducing nitrogen oxides in an exhaust gas to purify the exhaust gas, comprising:
- trapping means for trapping particulate matter in the exhaust gas;
- and
- an exhaust gas treating catalyst for reducing nitrogen oxides in an exhaust gas to purify the exhaust gas, the exhaust gas treating catalyst containing a complex oxide represented by a general formula ABO3, where
- the A-site is composed of a lanthanoid (La) and barium (Ba),
- the B-site is composed of iron (Fe), niobium (Nb) and palladium (Pd),
- further containing at least one additional precious metal (PM2) comprising Pt, Rh Ir and Ru, other than palladium (Pd), and
- fulfills PM2/−{LaxBa(1-x)}{FeyNb(1-y)}(1-z)PdzO3,
- where x is in a range of more than 0.30, but 0.95 or less, y is in a range of 0.07 or more, but 0.94 or less, and z is in a range of 0.01 or more, but 0.10 or less, and
- the complex oxide has such a structure that the barium functions as a NOx storing agent, and the niobium act on the palladium to accelerate NO oxidation and NOx reduction,
- the exhaust gas treating catalyst being disposed downstream of the trapping means in a flow-through direction of the exhaust gas,
- wherein the at least one precious metal is contained in an amount of 0.1 wt. % or more based on the complex oxide.
Dependencies are inferred from the claim text.