An exhaust gas purifying system for a gasoline engine with high NH.sub.3 purifying performance after duration is provided. The exhaust gas purifying system for a gasoline engine disclosed herein is configured to be disposed in an exhaust path of the gasoline engine. The exhaust gas purifying system includes an upstream catalyst converter including a first catalyst body and a downstream catalyst converter including a second catalyst body. The first catalyst body contains a catalyst precious metal. The second catalyst body has a structure in which an NH.sub.3 adsorption layer and a catalyst layer are stacked on a base material. The NH.sub.3 adsorption layer of the second catalyst body contains a zeolite as an NH.sub.3 adsorber. The catalyst layer of the second catalyst body contains a catalyst precious metal and an OSC material.

A metal oxide nanorod array structure according to embodiments disclosed herein includes a monolithic substrate having a surface and multiple channels, an interface layer bonded to the surface of the substrate, and a metal oxide nanorod array coupled to the substrate surface via the interface layer. The metal oxide can include ceria, zinc oxide, tin oxide, alumina, zirconia, cobalt oxide, and gallium oxide. The substrate can include a glass substrate, a plastic substrate, a silicon substrate, a ceramic monolith, and a stainless steel monolith. The ceramic can include cordierite, alumina, tin oxide, and titania. The nanorod array structure can include a perovskite shell, such as a lanthanum-based transition metal oxide, or a metal oxide shell, such as ceria, zinc oxide, tin oxide, alumina, zirconia, cobalt oxide, and gallium oxide, or a coating of metal particles, such as platinum, gold, palladium, rhodium, and ruthenium, over each metal oxide nanorod. Structures can be bonded to the surface of a substrate and resist erosion if exposed to high velocity flow rates.

Provided is an exhaust gas purification catalyst with excellent durability against exhaust gas including a poisoning substance. The exhaust gas purification catalyst includes a porous substrate, a catalyst coating layer formed on the porous substrate, and a dummy coating layer formed on the outermost surface of the catalyst coating layer. The catalyst coating layer has a carrier and a noble metal catalyst supported on the carrier. The dummy coating layer includes a carrier having at least alumina and does not include a noble metal catalyst. The dummy coating layer is formed to have a length which, from the end on the exhaust gas inlet side, is 10% to 70% of the entire length of the catalyst coating layer along the exhaust gas flow direction.

A NO.sub.x absorber catalyst for treating an exhaust gas from a diesel engine. The NO.sub.x absorber catalyst comprises a first NO.sub.x absorber material comprising a molecular sieve catalyst, wherein the molecular sieve catalyst comprises a noble metal and a molecular sieve, and wherein the molecular sieve contains the noble metal; a second NO.sub.x absorber material comprising palladium (Pd) supported on an oxide of cerium; and a substrate having an inlet end and an outlet end.

Systems and methods for separating hydrogen sulfide from carbon dioxide in a high-pressure mixed stream are disclosed herein. The methods include receiving the high-pressure mixed stream in an oxidation reactor and at an inlet pressure of at least 0.3 megapascals. The high-pressure mixed stream includes 0.01 to 5 mole percent hydrogen sulfide and at least 90 mole percent carbon dioxide. The methods further include oxidizing the high-pressure mixed stream with an oxidant to generate a high-pressure oxidized stream, includes oxidized hydrogen sulfide and carbon dioxide, at an oxidation pressure of at least 0.3 megapascals. The methods also include separating the high-pressure oxidized stream into an oxidized hydrogen sulfide product and a carbon dioxide product and generating the carbon dioxide product at a pressure of at least 0.3 megapascals. The systems include the high-pressure mixed stream, an oxidation reactor, and a separation assembly.

A system for recycling cooling devices, comprising a system part for catalytically oxidizing the pure hydrocarbon compounds and chlorofluorocarbons which accumulate during the recycling of the cooling devices. According to the invention, this system part comprises two reactors, provided mutually separated in the flow direction of the gases to be treated, a first reactor being used for catalytically oxidizing the pure hydrocarbon compounds while a second reactor is used for catalytically oxidizing chlorofluorocarbons.

Provided is an exhaust gas purification catalyst with excellent durability against exhaust gas including a poisoning substance. The exhaust gas purification catalyst includes a porous substrate, a catalyst coating layer formed on the porous substrate, and a dummy coating layer formed on the outermost surface of the catalyst coating layer. The catalyst coating layer has a carrier and a noble metal catalyst supported on the carrier. The dummy coating layer includes a carrier having at least alumina and does not include a noble metal catalyst. The dummy coating layer is formed to have a length which, from the end on the exhaust gas inlet side, is 10% to 70% of the entire length of the catalyst coating layer along the exhaust gas flow direction.

A passive NO.sub.x adsorber is disclosed. The passive NO.sub.x adsorber is effective to adsorb NO.sub.x at or below a low temperature and release the adsorbed NO.sub.x at temperatures above the low temperature. The passive NO.sub.x adsorber comprises a noble metal and a molecular sieve having an LTL Framework Type. The invention also includes an exhaust system comprising the passive NO.sub.x adsorber, and a method for treating exhaust gas from an internal combustion engine utilizing the passive NO.sub.x adsorber.

The invention relates to a wall-flow filter, to a method for the production and the use of the filter for reducing harmful exhaust gases of an internal combustion engine. The wall-flow filter was produced by exposing the filter at least twice successively to a powder-gas aerosol.

One aspect of the present invention is a gas treatment method including a step of causing a gas to be treated containing an acidic compound to be absorbed into a treatment solution phase-separated by absorption of the acidic compound, a step of separating the treatment solution, which is phase-separated into a first phase portion having relatively high content of the acidic compound and the second phase portion having relatively low content of the acidic compound as the acidic compound is absorbed, into a first solution mainly containing the first phase portion and a second solution mainly containing the second phase portion, a step of applying deoxygenation treatment to the separated second solution, and a step of heating the first solution together with the second solution to which the deoxygenation treatment is applied so as to release the acidic compound from the first solution and the second solution.