Disclosed are a tandem catalyst for synthesizing methyl acetate from carbon dioxide, a method for preparing the same, and a method for preparing methyl acetate using the same. The tandem catalyst of the present invention includes a first catalyst having a core-shell structure including a composite metal oxide core and a silica shell surrounding a surface of the composite metal oxide core, and a second catalyst including nano-ferrierite (N-FER) zeolite.

A structured catalyst for steam reforming of the present disclosure is used for producing reformed gas containing hydrogen from a reforming raw material containing hydrocarbon, and includes a support having a porous structure constituted of a zeolite-type compound, and at least one catalytic substance present inside the support. The support includes channels connecting with each other, and the catalytic substance is metal nanoparticles and present at least in the channels of the support.

A structured catalyst for steam reforming of the present disclosure is used for producing reformed gas containing hydrogen from a reforming raw material containing hydrocarbon, and includes a support having a porous structure constituted of a zeolite-type compound, and at least one catalytic substance present inside the support. The support includes channels connecting with each other, and the catalytic substance is metal nanoparticles and present at least in the channels of the support.

Catalytic compositions and sequential catalytic methods are generally described. In some embodiments, a composition comprises a first catalyst comprising a Cu-modified zeolite, and a second catalyst capable of a coupling reaction between (a) an intermediate resulting from a reaction of a reactant at the first catalyst, and (b) a co-reagent, wherein a rate of diffusion of the co-reagent within one or more cages and/or pores of the first catalyst is lower than a rate of diffusion of the intermediate within the one or more cages and/or pores of the first catalyst.

Catalytic compositions and sequential catalytic methods are generally described. In some embodiments, a composition comprises a first catalyst comprising a Cu-modified zeolite, and a second catalyst capable of a coupling reaction between (a) an intermediate resulting from a reaction of a reactant at the first catalyst, and (b) a co-reagent, wherein a rate of diffusion of the co-reagent within one or more cages and/or pores of the first catalyst is lower than a rate of diffusion of the intermediate within the one or more cages and/or pores of the first catalyst.

Provided is an SCR catalyst article comprising a substrate having thereon a second catalyst composition downstream of a first catalyst composition, wherein the first and second catalyst compositions are different and wherein the first catalyst composition is an SCR catalyst composition and the second catalyst composition comprises an Fe-loaded small- or medium-pore molecular sieve, the small- or medium-pore molecular sieve having a silica-to-alumina ratio (SAR) of from 6 to 19.

Provided is an SCR catalyst article comprising a substrate having thereon a second catalyst composition downstream of a first catalyst composition, wherein the first and second catalyst compositions are different and wherein the first catalyst composition is an SCR catalyst composition and the second catalyst composition comprises an Fe-loaded small- or medium-pore molecular sieve, the small- or medium-pore molecular sieve having a silica-to-alumina ratio (SAR) of from 6 to 19.

Disclosed is a catalyst composition and its use in a process for the conversion of a feedstock containing C.sub.8+ aromatic hydrocarbons to produce light aromatic products, comprising benzene, toluene and xylene. The catalyst composition comprises a first zeolite having a constraint index of 3 to 12, a second zeolite comprising a mordenite zeolite synthesized from TEA or MTEA, at least one first metal of Group 10 of the IUPAC Periodic Table, and at least one second metal of Group 11 to 15 of the IUPAC Periodic Table, wherein said mordenite zeolite has a mesopore surface area of greater than 30 m.sup.2/g and said mordenite zeolite comprises agglomerates composed of primary crystallites, wherein said primary crystallites have an average primary crystal size as measured by TEM of less than 80 nm and an aspect ratio of less than 2.

Disclosed is a catalyst composition and its use in a process for the conversion of a feedstock containing C.sub.8+ aromatic hydrocarbons to produce light aromatic products, comprising benzene, toluene and xylene. The catalyst composition comprises a first zeolite having a constraint index of 3 to 12, a second zeolite comprising a mordenite zeolite synthesized from TEA or MTEA, at least one first metal of Group 10 of the IUPAC Periodic Table, and at least one second metal of Group 11 to 15 of the IUPAC Periodic Table, wherein said mordenite zeolite has a mesopore surface area of greater than 30 m.sup.2/g and said mordenite zeolite comprises agglomerates composed of primary crystallites, wherein said primary crystallites have an average primary crystal size as measured by TEM of less than 80 nm and an aspect ratio of less than 2.

To provide a catalyst for purifying a combustion exhaust gas and a method for purifying a combustion exhaust gas. The denitration catalyst used in a method for purifying a combustion exhaust gas of removing a nitrogen oxide in the exhaust gas by making the catalyst into contact with the combustion exhaust gas having an alcohol as a reducing agent added thereto, contains zeolite as a support having supported thereon a catalyst metal, in a powder X-ray diffraction (XRD) measurement of the denitration catalyst a ratio (relative peak intensity ratio) r=I/J of a height I of a diffraction peak at a diffraction angle (2?) of from 7.8 to 10.0? and a height J of a diffraction peak at a diffraction angle (2?) of from 28.0 to 31.0? being in a range of from 3.0 to 5.0.