It is an object to provide a catalyst that can effectively purify exhaust gas, in particular, carbon monoxide (CO) in exhaust gas, emitted from a diesel engine, a production method therefor, and an exhaust gas purification method using the same. A diesel engine exhaust gas purification catalyst for purifying exhaust gas emitted from a diesel engine of the present invention comprises a precious metal and alumina and/or zeolite supported on a three-dimensional structure, and has peaks for not less than three different pore sizes in a pore size distribution measured by the mercury intrusion method, wherein one of the peaks is a peak 2 at a pore size of not less than 0.3 μm and less than 1.0 μm, and the pore volume of the peak 2 being greater than 3.1% of the total pore volume.

A photocatalyst filtration system for a vehicle includes a housing having an airflow path, and a filter configured to filter air flowing in the airflow path, the filter having a first photocatalyst and a second photocatalyst. The system further includes a first ultraviolet (UV) light source disposed proximate the filter and configured to energize the first photocatalyst, and a second UV light source disposed proximate the filter and configured to produce light having a shorter wavelength than light produced by the first UV light source, and configured to energize the second photocatalyst. One of the first photocatalyst or the second photocatalyst is configured to remove odor from the air. The other of the first photocatalyst or the second photocatalyst is configured to remove bacteria from the air.

The present invention relates to a three-way catalyst (TWC) for treatment of exhaust gases from internal combustion engines operated with a predominantly stoichiometric air/fuel ratio, so called spark ignited engines.

The presently claimed invention provides a layered catalytic article and an exhaust system. The catalytic article comprises a first layer comprising platinum, a first platinum group metal component other than platinum, a ceria-alumina composite, and an oxygen storage component; wherein platinum is supported on the ceria-alumina component; the platinum group metal component is selected from palladium, rhodium or a combination thereof and the platinum group metal component is supported on the oxygen storage component; a second layer comprising a second platinum group metal component; and a refractory alumina component, an oxygen storage component or a combination thereof; wherein the second platinum group component is selected from platinum, palladium, rhodium or a combination thereof; and a substrate, wherein the amount of platinum is 10 to 80 wt. %, based on the total weight of platinum, palladium and rhodium. The presently claimed invention also provides a process for the preparation of a layered catalytic article and use of the catalytic article and the exhaust system for purifying a gaseous exhaust stream comprising hydrocarbons, carbon monoxide, and nitrogen oxides.

Disclosed is an exhaust gas purification catalyst with a multilayered structure including an ultra-thin layer with a thickness of 20 micrometers or less and containing Rh, Pd, or both as at least one precious metal component, and to a method of manufacturing the same. The method includes a step of forming an ultra-thin layer having a thickness of 20 micrometers or less as the top layer of the catalyst by applying a polymer coating solution containing a polymer having a functional group capable of chelating with the precious metal component(s) on the surface of the multilayer structure of the catalyst. The disclosed catalyst exhibits improved removal efficiency for THC, CO, and NOx contained compared to an existing thin film-type catalyst. Since the disclosed catalyst is coated with a thin coating layer containing at least a portion of precious metal components, the disclosed catalyst exhibits improved performance while using the same amount of precious metal components as in conventional catalysts.

An ammonia oxidation catalyst device, including a substrate, a first catalyst coat layer and a second catalyst coat layer, wherein: the first catalyst coat layer includes inorganic oxide particles and a catalytic noble metal supported on the inorganic oxide particles; the second catalyst coat layer includes an NO.sub.x selective reduction catalyst and a proton zeolite H-Zeolite; the first catalyst coat layer is present on the substrate; and the second catalyst coat layer is present on the first catalyst coat layer.

An oven of this disclosure includes a heated catalyst assembly that reduces emissions during cooking cycles and, in particular, during air frying. The heated catalyst assembly resides between the cooking chamber and its exhaust vent and includes a thermal radiation source including at least one looped element, a first catalyst located toward the inlet in proximity to one side of the thermal radiation source and a second catalyst located in proximity to an opposite side of the thermal radiation heat source. The first and second catalysts are arranged in planes parallel to that of the thermal radiation heat source. The heated catalyst assembly reduces emissions of volatile organics to no greater than 6 ppm.

The present invention provides an exhaust gas purifying catalyst including a first catalyst layer (12). The first catalyst layer (12) includes a first section (14) and a second section (15) in an exhaust gas flow direction, the first section (14) being located on an upstream side in the exhaust gas flow direction relative to the second section (15). The first section (14) and the second section (15) both contain a catalytically active component including a specific element. A concentration of the specific element is higher in the first section (14) than in the second section (15). A concentration gradient of the specific element contained in the first section (14) in a thickness direction of the catalyst layer (12) is milder than a concentration gradient of the specific element contained in the second section (15) in the thickness direction.

An exhaust gas purifying catalyst includes: a wall-flow structure substrate including an inlet cell, an outlet cell, and a porous partition; a first catalyst layer formed inside the partition such that a thickness of the first catalyst layer is between 40% and 60%, inclusive, of an overall thickness T.sub.w of the partition; and a second catalyst layer formed inside the partition such that the second catalyst layer extends across an entire region of the partition in a thickness direction thereof.

A three-way catalyst article, and its use in an exhaust system for compressed natural gas engines, is disclosed. The catalyst article for treating exhaust gas from compressed natural gas (CNG) engine comprising: a substrate comprising an inlet end, an outlet end with an axial length L; a first catalytic region beginning at the outlet end and extending for less than the axial length L, wherein the first catalytic region comprises a first PGM component; and a second catalytic region beginning at the inlet end, wherein the second catalytic region comprises a second PGM component; wherein the first PGM component comprises palladium, platinum, or a combination thereof; and wherein the second PGM component comprises rhodium.