摘要:
A catalyst composition is provided having a zeolite material of a CHA crystal structure and a silica to alumina mole ratio (SAR) of about 10 to about 25 and preferably having a mean crystal size of at least 1.0 microns; and a non-aluminum base metal (M), wherein said zeolite material contains said base metal in a base metal to aluminum ratio (M:Al) of about 0.10 to about 0.24.
摘要:
A system for reducing ammonia (NH3) emissions includes (a) a first component comprising a first substrate containing a three-way catalyst, wherein the first component is disposed upstream of a second component comprising a second substrate containing an ammonia oxidation catalyst, wherein said ammonia oxidation catalyst comprises a small pore molecular sieve supporting at least one transition metal; and (b) an oxygen-containing gas input disposed between the components. For example, a CHA Framework Type small pore molecular sieve may be used. A method for reducing NH3 emission includes introducing an oxygen-containing gas into a gas stream to produce an oxygenated gas stream; and exposing the oxygenated gas stream to an NH3 oxidation catalyst to selectively oxidize at least a portion of the NH3 to N2. The method may further include the step of exposing a rich burn exhaust gas to a three-way catalyst to produce the gas stream comprising NH3.
摘要:
A system for reducing ammonia (NH3) emissions includes (a) a first component comprising a first substrate containing a three-way catalyst, wherein the first component is disposed upstream of a second component comprising a second substrate containing an ammonia oxidation catalyst, wherein said ammonia oxidation catalyst comprises a small pore molecular sieve supporting at least one transition metal; and (b) an oxygen-containing gas input disposed between the components. For example, a CHA Framework Type small pore molecular sieve may be used. A method for reducing NH3 emission includes introducing an oxygen-containing gas into a gas stream to produce an oxygenated gas stream; and exposing the oxygenated gas stream to an NH3 oxidation catalyst to selectively oxidize at least a portion of the NH3 to N2.
摘要:
Provided is a catalyst comprising (a) a zeolite material having a mean crystal size of at least about 0.5 μm, having a CHA framework that contains silicon and aluminum, and having a silica-to-alumina mole ratio (SAR) of about 10 to about 25; and (b) an extra-framework promoter metal (M) disposed in said zeolite material as free and/or exchanged metal, wherein the extra-framework promoter metal is copper, iron, and mixtures thereof, and is present in a promoter metal-to-aluminum atomic ratio (M:Al) of about 0.10 to about 0.24 based on the framework aluminum; and optionally comprising (c) at least about 1 weight percent of cerium in said zeolite material, based on the total weight of the zeolite, wherein said cerium is present in a form selected from exchanged cerium ions, monomeric ceria, oligomeric ceria, and combinations thereof, provided that said oligomeric ceria has a particle size of less than 5 μm.
摘要:
Provided is a catalyst comprising (a) a zeolite material having a mean crystal size of at least about 0.5 μm, having a CHA framework that contains silicon and aluminum, and having a silica-to-alumina mole ratio (SAR) of about 10 to about 25; and (b) an extra-framework promoter metal (M) disposed in said zeolite material as free and/or exchanged metal, wherein the extra-framework promoter metal is copper, iron, and mixtures thereof, and is present in a promoter metal-to-aluminum atomic ratio (M:Al) of about 0.10 to about 0.24 based on the framework aluminum; and optionally comprising (c) at least about 1 weight percent of cerium in said zeolite material, based on the total weight of the zeolite, wherein said cerium is present in a form selected from exchanged cerium ions, monomeric ceria, oligomeric ceria, and combinations thereof, provided that said oligomeric ceria has a particle size of less than 5 μm.
摘要:
A system for reducing ammonia (NH3) emissions includes (a) a first component comprising a first substrate containing a three-way catalyst, wherein the first component is disposed upstream of a second component comprising a second substrate containing an ammonia oxidation catalyst, wherein said ammonia oxidation catalyst comprises a small pore molecular sieve supporting at least one transition metal; and (b) an oxygen-containing gas input disposed between the components. For example, a CHA Framework Type small pore molecular sieve may be used. A method for reducing NH3 emission includes introducing an oxygen-containing gas into a gas stream to produce an oxygenated gas stream; and exposing the oxygenated gas stream to an NH3 oxidation catalyst to selectively oxidize at least a portion of the NH3 to N2. The method may further include the step of exposing a rich burn exhaust gas to a three-way catalyst to produce the gas stream comprising NH3.
摘要:
A method for oxidizing carbon monoxide (CO) and volatile organic compounds (VOCS) comprises contacting a gas containing water vapor and said CO and VOCs with a catalyst composition comprising at least one base metal promoter and at least one base metal catalyst supported on an oxide support material comprising one or more of alumina, silica, zirconia, ceria, and titania, wherein the VOCs comprise one or more of methyl acetate, methane, methyl bromide, benzene, methanol, methyl ethyl ketone, butane, and butene.
摘要:
A method for oxidizing carbon monoxide (CO) and volatile organic compounds (VOCS) comprises contacting a gas containing water vapor and said CO and VOCs with a catalyst composition comprising at least one base metal promoter and at least one base metal catalyst supported on an oxide support material comprising one or more of alumina, silica, zirconia, ceria, and titania, wherein the VOCs comprise one or more of methyl acetate, methane, methyl bromide, benzene, methanol, methyl ethyl ketone, butane, and butene.
摘要:
A catalyst washcoat is provided having a molecular sieve with a CHA crystal structure; about 0.5 to about 5.0 mol % phosphorus; and SiO2 and Al2O3 in a mole ratio of about 5 to about 40. The washcoat includes one or more promoters or stabilizers, and may be applied to a monolith substrate to produce a catalytically active article.
摘要:
A NOx storage material comprises a support, a potassium salt impregnated on the support, the potassium impregnated on the support is promoted with a platinum group metal, and wherein the NOx storage material has an electrical property which changes based on the amount of NOx loading on the NOx storage material. An apparatus for direct NOx measurement includes a sensor coated with the NOx storage material. A method of determining NOx flux in a NOx containing gas comprises exposing the gas to the apparatus and converting a signal developed by the apparatus to a signal representative of the NOx flux.