The present invention relates to the field of alkylation catalysts, and disclosed are a composite ZSM-5 molecular sieve, a preparation method therefor, a catalyst and an application thereof. A single crystal of the composite ZSM-5 molecular sieve comprises a main crystal and a twin crystal; the main crystal and the twin crystal are both ZSM-5 crystals; a crystal plane [010] of the main crystal is covered by a crystal plane [100] of the twin crystal; and the ratio of the number of sinusoidal pore openings to the number of straight pore openings on the outer surface of the single crystal of the composite ZSM-5 molecular sieve is (0.7-10:1), and the molar ratio Y1 of an Si element to an Al element within 10 nm of the surface is (300-2000):1. The single crystal of the composite ZSM-5 molecular sieve of the present invention has a large ratio of the number of sinusoidal pore openings to the number of straight pore openings, and is aluminum-poor on the surface and aluminum-rich on the inside. When applied to the toluene methanol alkylation reaction to prepare p-xylene, the selectivity of p-xylene may be greatly improved.

Disclosed herein are catalyst compositions having improved mercury intrusion volume and surface areas and processes for making these compositions. The enhanced compositions disclosed herein contain zirconium, cerium, optionally yttrium, and optionally one or more rare earths other than cerium and yttrium. Further disclosed are processes of producing these compositions involving supercritical drying after addition of mesitylene. The compositions can be used as a catalyst and/or as part of a catalyst system in an automobile exhaust system.

A method for preparing a core-shell structure photocatalytic material includes: obtaining a titanyl sulfate solution by mixing and reacting sulfuric acid and metatitanic acid; obtaining a mixed solution by adding a porous material having a hydrophilic surface into the titanyl sulfate solution; adding an alkali into the mixed solution to obtain a precipitation product by reacting the alkali with the titanyl sulfate coated on the surface of the porous material; and filtering, washing, drying and calcining the precipitation product to obtaining a core-shell structure photocatalytic material with the porous material as a core and a mesoporous quantum titanium oxide as a shell.

A method of making an oxygen storage material (OSM) with developed mesoporosity having a small fraction of pores <10 nm (fresh or aged), and resistance to thermal sintering is provided. This OSM is suitable for use as a catalyst and catalyst support. The method of making this oxygen storage material (OSM) includes the preparation of a solution containing pre-polymerized zirconium oligomers, cerium, rare earth and transition metal salts; the interaction of this solution with a complexing agent that has an affinity towards zirconium; the formation of a zirconium-based precursor; and the co-precipitation of all constituent metal hydroxide with abase.

A method of making an oxygen storage material (OSM) with developed mesoporosity having a small fraction of pores <10 nm (fresh or aged), and resistance to thermal sintering is provided. This OSM is suitable for use as a catalyst and catalyst support. The method of making this oxygen storage material (OSM) includes the preparation of a solution containing pre-polymerized zirconium oligomers, cerium, rare earth and transition metal salts; the interaction of this solution with a complexing agent that has an affinity towards zirconium; the formation of a zirconium-based precursor; and the co-precipitation of all constituent metal hydroxide with abase.

The present disclosure discloses a device and a method for continuously producing catalysts based on low-temperature coprecipitation. The device mainly includes: a metal salt preparation kettle, a primary reaction kettle, a secondary reaction kettle, a precipitant preparation kettle, a circulating refrigeration system, an automatic control system, a non-aqueous solvent storage tank and a water storage tank. Independent preparation kettles are provided for rapid dissolution of the raw materials, and can be used to prepare the raw materials for the next batch during the reactions that are carried out in the primary and secondary reaction kettles; the circulating refrigeration system refrigerates the primary and secondary reaction kettles, and thus during the reaction, the low-temperature precipitant makes it possible to offset the precipitation reaction heat and the heat caused by the stirring in the primary reaction kettle, and improve the refrigeration efficiency of the primary reaction kettle.

Metal-organic frameworks (MOFs) may have Zn(II), Pb(II), and/or Cd(II) as a central metal ion; a 4,4′-bipyridylethylene (bpe) ligand as a first ligand; and fumaric acid (fum) and/or oxalic acid (ox) as a second ligand, wherein the 4,4′-bipyridylethylene ligands are stacked in the MOF, and wherein a distance between two consecutive 4,4′-bipyridylethylene ligands is less than 5 Å. Cycloadditions, particularly photoinduced [2+2] cycloadditions may be catalyzed by such MOFs, and/or the conversion of photoinduced [2+2] cycloadditions in inventive MOFs may be increased by mechanical force, such as by grinding.

Methods of making an iron based catalyst using microwave hydrothermal synthesis are provided. The methods include dissolving iron(III) nitrate, Fe(NO.sub.3).sub.3, in an organic solvent to form a solution. Once dissolved, the methods include a step of neutralizing the solution with an alkaline mineralizing agent to obtain a precipitate. The solution with the precipitate is then subjected to microwave radiation to cause a temperature gradient and a hydrothermal crystallization process to form a synthesized product. The synthesized product is subsequently separated from the mineralizing agent. The method includes washing and drying the synthesized product to obtain particles of sodium iron oxide (NaFeO.sub.2) catalyst that can be used as a composition for a passive NO.sub.x adsorber. A two-stage NO.sub.x abatement device for removal of NO.sub.x from an exhaust gas stream during a cold start operation of an internal combustion engine is also provided.

The present invention relates to a supported nickel catalyst precursor comprising Ni, Si, Al, and O, wherein the catalyst precursor displays a specific total intrusion volume determined via Hg intrusion. Further, the present invention relates to a process for preparing said catalyst precursor. Yet further, the present invention relates to a supported nickel catalyst prepared from the said catalyst precursor. In addition thereto, the present invention relates to a use thereof in a hydrogenation reaction of aromatic compounds.

The present invention relates to a supported nickel catalyst precursor comprising Ni, Si, Al, and O, wherein the catalyst precursor displays a specific total intrusion volume determined via Hg intrusion. Further, the present invention relates to a process for preparing said catalyst precursor. Yet further, the present invention relates to a supported nickel catalyst prepared from the said catalyst precursor. In addition thereto, the present invention relates to a use thereof in a hydrogenation reaction of aromatic compounds.