The present disclosure provides SCR catalyst compositions capable of reducing nitrogen oxide (NO.sub.x) emissions in engine exhaust. The catalyst compositions include a reducible metal oxide support containing ceria, one or more transition metal oxides as a redox promotor; and an oxide of niobium, tungsten, silicon, molybdenum, or a combination thereof as an acidic promotor. The redox promotor and the acid promotor are both supported on the reducible metal oxide support. Further provided are SCR catalyst articles coated with such compositions, processes for preparing such catalyst compositions and articles, an exhaust gas treatment system including such catalyst articles, and methods for reducing NO.sub.x in an exhaust gas stream using such catalyst articles and systems.

The invention relates to noble metal-oxo clusters represented by the formula [M.sub.s(R.sub.2XO.sub.2).sub.z(OR′).sub.xO.sub.yX′.sub.q] or solvates thereof, corresponding supported noble metal-oxo clusters, and processes for their preparation, as well as corresponding metal cluster units, optionally in the form of a dispersion in a liquid carrier medium or immobilized on a solid support, and processes for their preparation, as well as their use in conversion of organic substrate.

The invention relates to noble metal-oxo clusters represented by the formula [M.sub.s(R.sub.2XO.sub.2).sub.z(OR′).sub.xO.sub.yX′.sub.q] or solvates thereof, corresponding supported noble metal-oxo clusters, and processes for their preparation, as well as corresponding metal cluster units, optionally in the form of a dispersion in a liquid carrier medium or immobilized on a solid support, and processes for their preparation, as well as their use in conversion of organic substrate.

A catalyst has a carrier and a hydrogenation active metal component supported on the carrier. The hydrogenation active metal component contains at least one Group VIB metal component and at least one Group VIII metal component, and the carrier is composed of phosphorus-containing alumina. When the hydrogenation catalyst is measured using a hydrogen temperature programmed reduction method (H.sub.2-TPR), the ratio of the peak height of the low-temperature reduction peak, P.sub.low-temp peak, at a temperature of 300-500° C. to the peak height of the high-temperature reduction peak, P.sub.hi-temp peak, at a temperature of 650-850° C., i.e. S=P.sub.low-temp peak/P.sub.hi-temp peak, is 0.5-2.0; preferably 0.7-1.9, and more preferably 0.8-1.8. The hydrogenation catalyst shows excellent heteroatom removal effect and excellent stability when used in hydrotreatment.

A catalyst has a carrier and a hydrogenation active metal component supported on the carrier. The hydrogenation active metal component contains at least one Group VIB metal component and at least one Group VIII metal component, and the carrier is composed of phosphorus-containing alumina. When the hydrogenation catalyst is measured using a hydrogen temperature programmed reduction method (H.sub.2-TPR), the ratio of the peak height of the low-temperature reduction peak, P.sub.low-temp peak, at a temperature of 300-500° C. to the peak height of the high-temperature reduction peak, P.sub.hi-temp peak, at a temperature of 650-850° C., i.e. S=P.sub.low-temp peak/P.sub.hi-temp peak, is 0.5-2.0; preferably 0.7-1.9, and more preferably 0.8-1.8. The hydrogenation catalyst shows excellent heteroatom removal effect and excellent stability when used in hydrotreatment.

Isomerization of normal paraffins to form branched paraffins may be complicated by significant cracking of C.sub.7+ paraffins under isomerization reaction conditions. This issue may complicate upgrading of hydrocarbon feeds having significant quantities of heavier normal paraffins. Cracking selectivity may be decreased by combining one or more naphthenic compounds with a feed mixture comprising at least one C.sub.7+ normal paraffin and/or by utilizing tungstated zirconium catalysts having decreased tungsten loading. Further, C.sub.5 and C.sub.6 normal paraffins may undergo isomerization in the presence of C.sub.7+ normal paraffins. Methods for isomerizing normal paraffins may comprise: providing a feed mixture comprising at least C.sub.5-C.sub.7 normal paraffins and lacking normal paraffins larger than C.sub.8; and contacting the feed mixture with a bifunctional mixed metal oxide catalyst under isomerization reaction conditions effective to form a product mixture comprising one or more branched paraffins formed from each of the C.sub.5-C.sub.7 normal paraffins.

Isomerization of normal paraffins to form branched paraffins may be complicated by significant cracking of C.sub.7+ paraffins under isomerization reaction conditions. This issue may complicate upgrading of hydrocarbon feeds having significant quantities of heavier normal paraffins. Cracking selectivity may be decreased by combining one or more naphthenic compounds with a feed mixture comprising at least one C.sub.7+ normal paraffin and/or by utilizing tungstated zirconium catalysts having decreased tungsten loading. Further, C.sub.5 and C.sub.6 normal paraffins may undergo isomerization in the presence of C.sub.7+ normal paraffins. Methods for isomerizing normal paraffins may comprise: providing a feed mixture comprising at least C.sub.5-C.sub.7 normal paraffins and lacking normal paraffins larger than C.sub.8; and contacting the feed mixture with a bifunctional mixed metal oxide catalyst under isomerization reaction conditions effective to form a product mixture comprising one or more branched paraffins formed from each of the C.sub.5-C.sub.7 normal paraffins.

A filtering system includes a catalyst filter including a plurality of channels through which air is introduced, and a light-emitting device arranged to irradiate light to the catalyst filter for catalyst activation, where the light-emitting device includes a light source array including a plurality of first light sources corresponding one-to-one with the plurality of channels. Each of the plurality of first light sources may include a substrate, a first light-emitting device on the substrate, and a capsule which seals the first light-emitting device on the substrate. Only one first light-emitting device is provided in the capsule, or a second light-emitting device is further provided together with the first light-emitting device in the capsule.

A filtering system includes a catalyst filter including a plurality of channels through which air is introduced, and a light-emitting device arranged to irradiate light to the catalyst filter for catalyst activation, where the light-emitting device includes a light source array including a plurality of first light sources corresponding one-to-one with the plurality of channels. Each of the plurality of first light sources may include a substrate, a first light-emitting device on the substrate, and a capsule which seals the first light-emitting device on the substrate. Only one first light-emitting device is provided in the capsule, or a second light-emitting device is further provided together with the first light-emitting device in the capsule.

Systems and methods for producing an isomerization product. One or more isomerization reactors comprising a catalyst may be used to process an isomerization feedstock comprising a primary n-paraffin reactant and hydrogen gas, and the isomerization reactor may be operated at a pressure parameter at which the partial pressure of the primary n-paraffin is within about 70% to about 130% of its equilibrium vapor pressure to isomerize the primary n-paraffin reactant.