A xenon adsorbent capable of efficiently adsorbing xenon, even at a low concentration, from a mixture gas is Provided.

A xenon adsorbent comprising a zeolite having a pore size in the range of 3.5 to 5 and a silica alumina molar ratio in the range of 10 to 30.

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.

Provided here are zirconium-substituted hierarchical zeolite compositions and methods of preparing such catalytic compositions. One such method involves subjecting the zirconium-substituted zeolite to a framework modification process using a single template to produce a framework-modified zeolite, followed by subjecting the framework-modified zeolite to an ion exchange process to produce a hierarchical zeolite composition. Also provided are methods of catalytic cracking of hydrocarbon feedstocks using these zirconium-substituted hierarchical zeolite compositions.

Provided here are zirconium-substituted hierarchical zeolite compositions and methods of preparing such catalytic compositions. One such method involves subjecting the zirconium-substituted zeolite to a framework modification process using a single template to produce a framework-modified zeolite, followed by subjecting the framework-modified zeolite to an ion exchange process to produce a hierarchical zeolite composition. Also provided are methods of catalytic cracking of hydrocarbon feedstocks using these zirconium-substituted hierarchical zeolite compositions.

This application consists of a method for the synthesis of a type of FER/MOR composite molecular sieve. That method consisting of mixing FER seed crystals, MOR seed crystals, a silicon source, water and an acid or alkali, thus yielding a reaction mixture; by adjusting the proportions of the seed crystals added, the silicon-aluminium proportion, acidity/alkalinity and other reaction conditions, it is possible to obtain a dual phase composite molecular sieve within which the proportions of the crystal phases may be adjusted. In the synthesis process to which the method of this application relates, there is no need to add any organic template, thus reducing the cost of the reaction, in addition to reducing likely environmental pollution, thus having major potential applications.

SCR-active molecular-sieve based catalysts with improved low-temperature performance are made by heating a molecular-sieve in a non-oxidizing atmosphere with steam (hydrothermal treatment), or in a reducing atmosphere without steam (thermal treatment), at a temperature in the range of 600-900? C. for a time period from 5 minutes to two hours. The resulting SCR-active iron-containing molecular sieves exhibit a selective catalytic reduction of nitrogen oxides with NH.sub.3 or urea at 250? C. that is at least 50% greater than if the iron-containing molecular-sieve were calcined at 500? C. for two hours without performing the hydrothermal or thermal treatment.

SCR-active molecular-sieve based catalysts with improved low-temperature performance are made by heating a molecular-sieve in a non-oxidizing atmosphere with steam (hydrothermal treatment), or in a reducing atmosphere without steam (thermal treatment), at a temperature in the range of 600-900? C. for a time period from 5 minutes to two hours. The resulting SCR-active iron-containing molecular sieves exhibit a selective catalytic reduction of nitrogen oxides with NH.sub.3 or urea at 250? C. that is at least 50% greater than if the iron-containing molecular-sieve were calcined at 500? C. for two hours without performing the hydrothermal or thermal treatment.

Provided here are zirconium-substituted hierarchical zeolite compositions and methods of preparing such catalytic compositions. One such method involves subjecting the zirconium-substituted zeolite to a framework modification process using a single template to produce a framework-modified zeolite, followed by subjecting the framework-modified zeolite to an ion exchange process to produce a hierarchical zeolite composition. Also provided are methods of catalytic cracking of hydrocarbon feedstocks using these zirconium-substituted hierarchical zeolite compositions.

Provided here are zirconium-substituted hierarchical zeolite compositions and methods of preparing such catalytic compositions. One such method involves subjecting the zirconium-substituted zeolite to a framework modification process using a single template to produce a framework-modified zeolite, followed by subjecting the framework-modified zeolite to an ion exchange process to produce a hierarchical zeolite composition. Also provided are methods of catalytic cracking of hydrocarbon feedstocks using these zirconium-substituted hierarchical zeolite compositions.

The present disclosure provides a molecular sieve, a sound absorbing material using the molecular sieve, and a speaker. The molecular sieve is a core-shell molecular sieve. The core-shell molecular sieve includes a core phase molecular sieve and a shell layer molecular sieve. The shell layer molecular sieve has a greater average pore diameter than the core phase molecular sieve. The porous shell layer molecular sieve having the greater pore diameter can protect the internal functioning micropores from being blocked, so that a resonant frequency f.sub.0 of a same volume of molecular sieve can be reduced, the bass effect and performance stability are significantly improved.