摘要:
A catalyst having high temperature (800.degree.-1050.degree. C.) stability and improved three-way automotive exhaust gas catalyst activity at high temperatures, comprising an outer catalytic coating of binary La-Pd oxide (La.sub.2 Pd.sub.2 O.sub.5 or La.sub.4 PdO.sub.7) calcined and supported on a catalyst-supporting substrate, the oxide being present in an amount to provide 15-150 g of Pd per cubic foot of the substrateA method of making binary La-Pd oxides useful as an automotive exhaust catalyst operative at high temperatures, comprising heating in an oxidizing atmosphere a mixture containing La compounds and Pd compounds in a La:Pd ratio of 1:1 or 4:1, the heating being staged to first heat slowly from about 50.degree. C. to start decomposition of the compounds and thereafter retaining the residue at an elevated temperature to stimulate growth of crystalline binary La-Pd oxides and to calcine the crystalline oxides.A method of making an automotive catalyst by suspending binary La-Pd oxides in a sol (preferably alumina sol) and depositing and fixing such sol suspension on a substrate coated with conventional washcoats.
摘要:
A three-way catalyst system for treating the exhaust stream of a compressed natural gas (CNG) fueled engine operating slightly rich of stoichiometry, the said catalyst system providing high conversions and low light-off temperature for the removal of HC, CO, and NO.sub.x. A high surface area gamma alumina support is impregnated with an intimate mixture of 0.2-30% Pd and 0.5-20% La.sub.2 O.sub.3, the Pd being in crystalline form with particle size in the range of 5-500 angstroms.A method of making such catalyst system comprising sequentially impregnating a high surface area gamma alumina support with lanthana and palladium by incipient wetness techniques, such techniques comprising the procedure of contacting alumina first with a lanthanum nitrate solution of desired concentration to obtain 0.5-20% lanthana, contacting the lanthana impregnated alumina with a palladium nitrate solution of desired concentration to obtain a 0.2-30% palladium content in the catalyst, each of said steps being separated by drying and calcination.A method of treating exhaust gas from a CNG fueled engine with the catalyst system described above, comprising: (a) operating said engine at slightly rich of stoichiometry; (b) exposing such catalyst to the exhaust gases in the range of 400.degree.-750.degree. C. and at a space velocity in the range of 0-100K hr.sup.-1, said exhaust gas being converted at an efficiency greater than 90% for each of NO, CO, and CH.sub.4.
摘要:
A three-way catalyst for automotive emission control having a mechanical carrier having a support comprised substantially of alumina, a catalytic compound supported on said carrier having a major constituent of palladium, and a discontinuous phase of titanium oxide on or adjacent substantially each exposed particle of the catalytic compound. A method of making a three-way catalyst for automotive emission control, comprising: impregnating with palladium a mechanical carrier having a support comprised substantially of alumina to produce a composite having 0.05-5.0% palladium; and impregnating the composite with an organo-titanium compound and decomposing such impregnated compound to form a discontinuous titanium oxide phase on or adjacent the exposed portions of said composite.
摘要:
A method of making a three-way catalyst based on platinum group metals, comprising: (a) impregnating an alumina substrate with a platinum group metal ion by contacting such substrate with an aqueous solution containing the platinum group metal in an amount of 0.1-5% by weight of alumina substrate and a water soluble acid that forms RCOOH with R being an alkyl or equivalent, said acid being present in an amount of 10-120% by weight of the alumina substrate, the pH of said solution being less than 4.0; and (b) drying and calcining the wetted substrate without sintering said substrate.The three-way catalyst construction based on platinum group metals has enhanced catalytic activity. It comprises an alumina substrate and a platinum group metal impregnation layer thereover, said impregnation layer being comprised of raft-like particle structures, each having increased metal density resulting from the nesting of both small and large metal particles within a given volume.
摘要:
A method of making a three-way catalyst based on platinum group metals, comprisng: (a) impregnating an alumina substrate with a platinum group metal ion by contacting such substrate with an aqueous solution containing the platinum group metal in an amount of 0.1-5% by weight of alumina substrate and a water soluble acid that forms RCOOH with R being an alkyl or equivalent, said acid being present in an amount of 10-120% by weight of the alumina substrate, the pH of said solution being less than 4.0; and (b) drying and calcining the wetted substrate without sintering said substrate.The three-way catalyst construction based on platinum group metals has enhanced catalytic activity. It comprises an alumina substrate and a platinum group metal impregnation layer thereover, said impregnation layer being comprised of raft-like particle structures, each having increased metal density resulting from the nesting of both small and large metal particles within a given volume.
摘要:
A three-way catalyst system for treating the exhaust stream of a compressed natural gas (CNG) fueled engine operating slightly rich of stoichiometry, the said catalyst system providing high conversions and low light-off temperature for the remnoval of HC, CO, and NO.sub.x. A high surface area gamma alumina support is impregnated with an intimate mixture of 0.2-30% Pd and 0.5-20% La.sub.2 O.sub.3, the Pd being in crystalline form with a particle size in the range of 5.500 angstroms.A method of making such catalyst system comprising sequentially impregnating a high surface area gamma alumina support with lanthana and palladium by incipient wetness techniques, such techniques comprising the procedure of contacting alumina first with a lanthanum nitrate solution of desired concentration to obtain 0.5-20% lanthana, contacting the lanthana impregnated alumina with a palladium nitrate solution of desired concentration to obtain a 0.2-30% palladium content in the catalyst, each of said steps being separated by drying and calcination.A method of treating exhaust gas from a CNG fueled engine with the catalyst system described above, comprising: (a) operating said engine at slightly rich of stoichiometry; (b) exposing such catalyst to the exhaust gases in the range of 400.degree.-750.degree. C. and at a space velocity in the range of 0-100 K hr.sup.-1, said exhaust gas being converted at an efficiency greater than 90% for each of NO, CO, and CH.sub.4.
摘要:
The present invention broadly relates to a catalyst for promoting the oxidation-reduction reactions of the exhaust gases produced by an internal combustion engine wherein the catalyst comprises; tungsten oxide, a basic metal oxide, and a noble metal. More narrowly, the present invention relates to a catalyst for promoting oxidation-reduction reactions with the exhaust gases produced by internal combustion engine wherein the catalyst comprises; a composite oxide comprised of a refractory oxide, tungsten oxide in juxtaposed relation with the refractory oxide, and a basic metal oxide in juxtaposed relation with the tungsten oxide; and arrayed on the composite oxide a noble metal.
摘要:
Sacrificial use of amino polymers to modify the crystal structure of platinum derived from chlorine compounds in a method to oxidize hydrocarbons, comprising: (a) preparing a polymer modifier by controllably reacting amine with epoxy resin to form a soluble adduct and adding to the adduct a solvent to form a homogeneous amino polymer solution; (b) coating a granular support material with platinum/chlorine compounds; and (c) mixing the coated support material with the polymer solution and heating the mixture to evaporate the solvent and to decompose and eliminate the polymer, leaving the coated granules with platinum in a morphologically changed condition devoid of amino polymer but having enhanced catalytic effectiveness for promoting oxidation of hydrocarbons. The amine is of a primary or secondary amine, preferably the hydroxyethyl group. The epoxy is a soluble resin comprising two or more epoxide groups per molecule, i.e., dihydric phenol or dihydric alcohol. The polymer modifier is preferably a soluble amino polymer having a molecular weight of 500-50,000 and advantageously is 50% or more by weight of the solution.
摘要:
A method of making an oxidation catalyst for use in automotive exhaust gas treatment by impregnating with platinum a mechanical carrier having a support comprised substantially of alumina to produce a composite having, by weight, 1-5% platinum, and impregnating (by incipient wetness) the composite with an organo-titanium compound (titanium butoxide) and decomposing such compound to form a discontinuous titanium oxide phase on or adjacent the exposed portions of the composite.A method of treating automotive exhaust gases carrying hydrocarbons is also disclosed, comprising initiating combustion in an internal combustion engine fueled with fossil fuel, placing an oxidation catalyst at a location in close proximity to the source of such emissions, and exposing at such location the exhaust gases to a catalyst consisting of an Al.sub.2 O.sub.3 substrate, a continuous coating of platinum in an amount of 0.1-5% by weight, and a complexing discontinuous phase of titania thereover in an amount of 0.1-2.5%.
摘要:
Method of enhancing the catalytic effectiveness of rhodium to reduce nitric oxides: (a) preparing a polymer modifier (molecular weight of 500-50,000) by controllably reacting amine [mono-2-hydroxyl ethyl amine and di-2-hydroxy ethyl amine] with epoxy resin (two or more epoxide groups per molecule) to form a soluble adduct and adding to the adduct a solvent to form a homogeneous amino polymer solution; (b) coating a granular support material (gamma alumina) with rhodium chloride and/or rhodium nitrate compounds; and (c) mixing the coated support material with added amino polymer solution to the support material either prior to or subsequent to step (b) and heating the mixture of polymer solution, support material, and rhodium chloride and/or rhodium nitrate compounds to evaporate the solvent and to decompose and eliminate the polymer, leaving the coated support material with rhodium in a morphologically changed condition devoid of amino polymer but having enhanced catalytic effectiveness for promoting reduction of nitric oxide.