摘要:
The present disclosure provides SCR catalyst compositions, catalyst articles, and catalyst systems, as well as methods of reducing the amount of NOx present in an engine exhaust gas, particularly exhaust from a gasoline engine. The catalyst compositions particularly can comprise a doped ceria substrate, particularly a ceria support doped with at least a niobia component, and optionally further doped with a further material, particularly a base metal oxide (BMO).
摘要:
The invention provides a selective catalytic reduction (SCR) catalyst effective in the abatement of nitrogen oxides (NOx), the SCR catalyst comprising a metal-promoted molecular sieve promoted with a metal selected from iron, copper, and combinations thereof, wherein the metal is present in an amount of 2.6% by weight or less on an oxide basis based on the total weight of the metal-promoted molecular sieve. A catalyst article, an exhaust gas treatment system method, and a method treating an exhaust gas stream, each comprising the SCR catalyst of the invention, are also provided. The SCR catalyst is particularly useful for treatment of exhaust from a lean burn gasoline engine.
摘要:
Zeolite catalysts and systems and methods for preparing and using zeolite catalysts having the CHA crystal structure are disclosed. The catalysts can be used to remove nitrogen oxides from a gaseous medium across a broad temperature range and exhibit hydrothermal stable at high reaction temperatures. The zeolite catalysts include a zeolite carrier having a silica to alumina ratio from about 15:1 to about 256:1 and a copper to alumina ratio from about 0.25:1 to about 1:1.
摘要:
Zeolite catalysts and systems and methods for preparing and using zeolite catalysts having the CHA crystal structure are disclosed. The catalysts can be used to remove nitrogen oxides from a gaseous medium across a broad temperature range and exhibit hydrothermal stable at high reaction temperatures. The zeolite catalysts include a zeolite carrier having a silica to alumina ratio from about 15:1 to about 256:1 and a copper to alumina ratio from about 0.25:1 to about 1:1.
摘要:
Zeolite catalysts and systems and methods for preparing and using zeolite catalysts having the CHA crystal structure are disclosed. The catalysts can be used to remove nitrogen oxides from a gaseous medium across a broad temperature range and exhibit hydrothermal stable at high reaction temperatures. The zeolite catalysts include a zeolite carrier having a silica to alumina ratio from about 15:1 to about 256:1 and a copper to alumina ratio from about 0.25:1 to about 1:1.
摘要:
Zeolite catalysts and systems and methods for preparing and using zeolite catalysts having the CHA crystal structure are disclosed. The catalysts can be used to remove nitrogen oxides from a gaseous medium across a broad temperature range and exhibit hydrothermal stable at high reaction temperatures. The zeolite catalysts include a zeolite carrier having a silica to alumina ratio from about 15:1 to about 256:1 and a copper to alumina ratio from about 0.25:1 to about 1:1.
摘要:
A catalyst for the treatment of exhaust gas emissions is disclosed. The catalyst can comprise ceria-alumina particles having a ceria phase present in a weight percent of the composite in the range of about 20% to about 80% on an oxide basis, an alkaline earth metal component supported on the ceria-alumina particles, wherein the CeO2 is present in the form of crystallites that are hydrothermally stable and have an average crystallite size less than 160 Å after aging at 950° C. for 5 hours in 2% O2 and 10% steam in N2.
摘要翻译:公开了一种用于处理废气排放的催化剂。 该催化剂可以包括二氧化铈 - 氧化铝颗粒,二氧化铈相以氧化物为基准存在于复合材料的重量百分比范围为约20%至约80%的二氧化铈相,负载在二氧化铈 - 氧化铝颗粒上的碱土金属组分,其中 CeO 2以水热稳定的形式存在,并且在950℃下在2%O 2和10%蒸气在N 2中老化5小时后具有小于160的平均微晶尺寸。
摘要:
A lean NOx trap for the treatment of exhaust gas emissions, such as the oxidation of unburned hydrocarbons (HC), and carbon monoxide (CO), and the trapping and reduction of nitrogen oxides (NOx) is disclosed. Nitrogen oxide storage catalysts can comprise a layer on a substrate including ceria-alumina particles having a ceria phase present in a weight percent of the composite in the range of about 20% to about 80% on an oxide basis, an alkaline earth metal component supported on the ceria-alumina particles, wherein the CeO2 is present in the form of crystallites that are hydrothermally stable and have an average crystallite size less than 130 Å after aging at 950° C. for 5 hours in 2% O2 and 10% steam in N2.
摘要:
Described are compositions and catalytic articles comprising both a first molecular sieve promoted with copper and a second molecular sieve promoted with iron, the first and second molecular sieves having a d6r unit and the first molecular sieves having cubic shaped crystals with an average crystal size of about 0.5 to about 2 microns. The weight ratio of the copper-promoted molecular sieve to the iron-promoted molecular sieve can be about 1:1 to about 4:1. The catalytic articles are useful in methods and systems to catalyze the reduction of nitrogen oxides in the presence of a reductant.
摘要:
A catalyst for the treatment of exhaust gas emissions is disclosed. The catalyst can comprise ceria-alumina particles having a ceria phase present in a weight percent of the composite in the range of about 20% to about 80% on an oxide basis, an alkaline earth metal component supported on the ceria-alumina particles, wherein the CeO2 is present in the form of crystallites that are hydrothermally stable and have an average crystallite size less than 160 Å after aging at 950° C. for 5 hours in 2% O2 and 10% steam in N2.