The present disclosure generally provides selective catalytic reduction (SCR) catalyst compositions, catalyst articles and catalyst systems including such catalyst articles for treating engine exhaust gas. In particular, the SCR catalyst composition includes a first zeolite and a second zeolite and has not been subjected to temperatures above 650° C. The first zeolite includes a promoter metal and has a first framework structure and at least a portion of the second zeolite is in a form selected from H.sup.+ form, NH.sub.4.sup.+ form, alkali metal form, alkaline earth metal form, and combinations thereof and has a second framework structure. The first framework structure and the second framework structure are different.

Direct conversion of syngas to light olefins is carried out in a fixed bed or a moving bed reactor with a composite catalyst A+B. The active ingredient of catalyst A is active metal oxide; and catalyst B is one or more than one of zeolite of CHA and AEI structures or metal modified CHA and/or AEI zeolite. A spacing between geometric centers of the active metal oxide of the catalyst A and the particle of the catalyst B is 5 m-40 mm. A spacing between axes of the particles is preferably 100 m-5 mm, and more preferably 200 m-4 mm. A weight ratio of the active ingredients in the catalyst A and the catalyst B is within a range of 0.1-20 times, and preferably 0.3-5.

Direct conversion of syngas to light olefins is carried out in a fixed bed or a moving bed reactor with a composite catalyst A+B. The active ingredient of catalyst A is active metal oxide; and catalyst B is one or more than one of zeolite of CHA and AEI structures or metal modified CHA and/or AEI zeolite. A spacing between geometric centers of the active metal oxide of the catalyst A and the particle of the catalyst B is 5 m-40 mm. A spacing between axes of the particles is preferably 100 m-5 mm, and more preferably 200 m-4 mm. A weight ratio of the active ingredients in the catalyst A and the catalyst B is within a range of 0.1-20 times, and preferably 0.3-5.

The present disclosure provides a sound absorbing material. The sound absorbing material comprising a heteroatom zeolite molecular sieve comprising a framework and an extra-framework cation, the framework comprising SiO2 and a metal oxide MxOy comprising a metal element M, wherein the framework has a molar ratio of Si/M between 250 to 500, wherein the M includes Fe, and that the extra-framework cation is at least one of a monovalent copper ion, a monovalent silver ion, a monovalent gold ion, an alkali metal ion or an alkaline earth metal ion. The sound absorbing material provided by the present disclosure, sound absorbing material to have better oxygen adsorption capacity, good waster repellency and stability. When such a sound absorbing material is applied to a speaker box, the speaker box will have better low frequency acoustic performance and better reliability.

The present disclosure provides a sound absorbing material. The sound absorbing material comprising a heteroatom zeolite molecular sieve comprising a framework and an extra-framework cation, the framework comprising SiO2 and a metal oxide MxOy comprising a metal element M, wherein the framework has a molar ratio of Si/M between 250 to 500, wherein the M includes Fe, and that the extra-framework cation is at least one of a monovalent copper ion, a monovalent silver ion, a monovalent gold ion, an alkali metal ion or an alkaline earth metal ion. The sound absorbing material provided by the present disclosure, sound absorbing material to have better oxygen adsorption capacity, good waster repellency and stability. When such a sound absorbing material is applied to a speaker box, the speaker box will have better low frequency acoustic performance and better reliability.

A molecular sieve has a silica/alumina molar ratio of 100-300, and has a mesopore structure. One closed hysteresis loop appears in the range of P/P.sub.0=0.4-0.99 in the low temperature nitrogen gas adsorption-desorption curve, and the starting location of the closed hysteresis loop is in the range of P/P.sub.0=0.4-0.7. The catalyst formed from the molecular sieve as a solid acid not only has a good capacity of isomerization to reduce the freezing point, but also can produce a high yield of the product with a lower pour point. The process for preparing the catalyst involves steps including crystallization, filtration, calcination, and hydrothermal treatment.

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.

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.

The purpose of the present invention is to provide a beta zeolite which includes zinc and has a small particle size. This beta zeolite includes a silicon oxide and a zinc oxide, and has an average particle size of 50 to 100 nm at a cumulative frequency of 50% in a particle size distribution measured by scanning electron microscope observation.

The purpose of the present invention is to provide a beta zeolite which includes zinc and has a small particle size. This beta zeolite includes a silicon oxide and a zinc oxide, and has an average particle size of 50 to 100 nm at a cumulative frequency of 50% in a particle size distribution measured by scanning electron microscope observation.