The present inventive concept relates to a surface-modified zeolite for direct air capture, and more particularly, to a zeolite for carbon dioxide capture whose surface is modified through sodium ion exchange. The zeolite for carbon dioxide capture is prepared by mixing a zeolite support and a supporting solution to form a mixed solution, heating the mixed solution to perform ion exchange, followed by evaporation, washing, drying and calcining. The resulting zeolite for carbon dioxide capture exhibits excellent CO.sub.2 absorption/desorption performance and maintains consistent catalytic activity, allowing for reuse.

An exhaust system for treating an exhaust gas from an internal combustion engine is disclosed. The system comprises a modified lean NO.sub.x trap (LNT), a urea injection system, and an ammonia-selective catalytic reduction (NH.sub.3-SCR) catalyst. The modified LNT comprises platinum, palladium, barium, and a ceria-containing material, and has a platinum:palladium molar ratio of at least 3:1. The modified LNT stores NO.sub.x at temperatures below about 200? C. and releases the stored NO.sub.x at temperatures above about 200? C. The urea injection system injects urea at temperatures above about 180? C.

A porous ceramic honeycomb body including a substrate of intersecting porous walls forming axial channels extending from a first end face to a second end face. An active portion of the walls include a zeolite catalyst disposed inside pores thereof and/or is comprised of an extruded zeolite and a three way catalyst (TWC) is disposed on wall surfaces of at least a portion of the active portion.

Disclosed is a preparation method for a molecular sieve-multiple oxide composite integral extrusion type denitration catalyst, belonging to the technical fields of atmosphere pollution control and environment-friendly catalytic materials. The preparation method comprises: constructing an organic structure coating on the surface of a metal ion-exchanged molecular sieves and synchronously adding multiple oxide components, thus obtaining an ion-exchanged molecular sieve-multiple oxide composite denitration catalyst active component; and then mixing, kneading into paste, staling, carrying out integral extrusion forming, drying, and calcining, thus obtaining the integral extrusion type denitration catalyst. The molecular sieve-multiple oxide composite integral extraction type denitration catalyst has a denitration efficiency more than 80% at the temperature ranging from 250 C. to 420 C. in the presence of 10% steam and 500 ppm sulfuric dioxide. According to the present invention, the application field of metal-loaded molecular sieve denitration catalysts is widened, and thus the metal-loaded molecular sieve denitration catalysts can be widely applied to the flue gas denitration of stationary sources.

The manufacturing method includes a step of mixing a coarse particle zeolite, a fine particle zeolite, and a raw material of an inorganic bonding material to prepare a zeolite raw material; a step of forming the prepared zeolite raw material into a honeycomb shape to prepare a honeycomb formed body; and a step of firing the prepared honeycomb formed body to prepare the honeycomb structure. In the step of preparing the zeolite raw material, as the coarse particle zeolite, a chabazite type zeolite having a specific average particle diameter, the fine particle zeolite having a specific average particle diameter, the raw material of the inorganic bonding material which includes at least basic aluminum lactate is used.

Extruded honeycomb catalyst bodies and methods of manufacturing same. The catalyst body includes a first oxide selected from the group consisting of tungsten oxides, vanadium oxides, and combinations thereof, a second oxide selected from the group consisting of cerium oxides, lanthanum oxides, zirconium oxides, and combinations thereof, and a zeolite.

Catalysts comprising metal-loaded non-zeolitic molecular sieves having the CHA crystal structure, including Cu-SAPO-34, and methods for treating exhaust gas incorporating such catalysts are disclosed. The catalysts can be used to remove nitrogen oxides from a gaseous medium across a broad temperature range and exhibit hydrothermal stability at high reaction temperatures.

Provided are a low-temperature SCR catalyst for denitrating diesel vehicle exhaust, and preparation method thereof. The catalyst uses a molecular sieve as a carrier, and uses metallic elements such as copper and iron as active components. The catalyst preparation method comprises: preprocessing the molecular sieve; conducting multiple equal-volume impreparations; after impreparation, drying to dehydrate, and calcining; and finally pulping and coating to prepare the catalyst. The catalyst employs base metals such as copper and iron instead of precious metals as active components, thus reducing costs, being harmless to humans, and being environmentally friendly. The preparation method of the catalyst is simple and feasible with low requirements for raw materials, employs a repeated but small-quantity method of equal volume impregnation; and enables active ions to be dispersed more uniformly as compared with the existing conventional preparation methods, thus improving utilization and improving low-temperature catalytic activity and durability.

A method of converting nitrogen oxides in a gas to nitrogen by contacting the nitrogen oxides with a nitrogenous reducing agent in the presence of a zeolite catalyst containing at least one transition metal, wherein the zeolite is a small pore zeolite containing a maximum ring size of eight tetrahedral atoms, wherein the at least one transition metal is selected from the group consisting of Cr, Mn, Fe, Co, Ce, Ni, Cu, Zn, Ga, Mo, Ru, Rh, Pd, Ag, In, Sn, Re, Jr and Pt.

A synthesis method for a selective catalytic reduction (SCR) catalyst results in the fabrication of Fe/ZSM-5 catalyst with almost exclusively isolated Fe species. The process allows to get more insight into the structure and role of Fe isolated species using in-situ X-ray absorption spectroscopy. The results point to the existence of distorted square-planar Fe2+ species under reducing atmosphere, which is in good agreement with XANES simulations. At lower temperatures Fe species are partially moving out of square-planar to distorted square pyramidal geometry, which is caused by adsorption of one of the reactants. This further improves the understanding of structure-activity relationships and rational development and the application of Fe zeolites in NOx abatement.