Visible-light response hybrid aerogel and a preparation method and application thereof in waste gas processing are disclosed. Dicyandiamide is taken as a precursor and is calcined in two times to prepare a carbon nitride nanosheet; the carbon nitride nanosheet is dispersed in water, silver metavanadate quantum dots are subjected to in-situ growth to prepare a silver metavanadate quantum dot/carbon nitride nanosheet composite material; the silver metavanadate quantum dot/carbon nitride nanosheet composite material and graphene oxide carry out hydrothermal reaction, and are then frozen and dried to prepare silver metavanadate quantum dot/carbon nitride nanosheet/graphene hybrid aerogel which is the visible-light response hybrid aerogel. The problems of large reduction dosage, serious secondary pollution, complexity in operation and the like generated when waste gas is processed by a traditional flue gas denitration technology are overcome.

A reactor for reducing the concentration of NOx in a stream comprising: an inlet for the stream; an outlet for a stream containing a reduced concentration of NOx; one or more catalyst beds comprising a ceramic or metallic foam with a NOx reduction catalyst; one or more flow paths from the inlet to the outlet that passes through at least one catalyst bed wherein the catalyst beds are closed at the top and bottom so that the flow path through the catalyst bed passes through the sides of the catalyst bed in a lateral flow is described.

Provided is an exhaust gas purification catalyst that suppresses phosphorus poisoning and improves long-term durability. The exhaust gas purification catalyst includes a phosphorus collection layer and a catalyst layer containing at least one precious metal element MP selected from the group consisting of Pt, Pd, and Rh, wherein the phosphorus collection layer is arranged on the upper layer side and/or the upstream side with respect to the catalyst layer; the phosphorus collection layer contains a composite oxide containing Al and an alkaline earth metal element M.sup.a that includes Mg and that may include at least one selected from the group consisting of Ca, Sr, and Ba, and having a cubic spinel structure belonging to the space group Fd-3m; the composite oxide has a M.sup.a/A1 molar ratio in a range of 0.02 or more and 0.60 or less; and the composite oxide has a peak derived from the cubic spinel structure belonging to the space group Fd-3m of the composite oxide between a diffraction angle 2θxm.sup.ao that is a position of a peak derived from an alkaline earth metal oxide M.sup.aO and a diffraction angle 2θx.sub.Al203 that is a position of a peak derived from an aluminum oxide Al.sub.2O.sub.3 in an X-ray diffraction spectrum.

A propulsion element including a catalyzing reactor is disclosed. The catalyzing reactor comprises a reactor entrance and a reactor exit and an internal structure arranged for flowing a reacting medium through the reactor from the reactor entrance to the reactor exit. The reactor structure comprising at least one thin walled reactor channel arranged between the entrance and the exit of the reactor. The channel having a channel wall that includes a catalyst and that defines a flow path, in which channel in use, a catalyzed exothermic reaction takes place in the medium as it flows along the flow path. The at least one channel is looped to have a portion of its flow path that is downstream with respect to the reactor entrance in heat exchanging contact with a portion of a flow path that is that is more upstream with respect to the reactor entrance, so as to transfer heat between a downstream portion of the reacting medium to an upstream portion thereof.

Certain selective catalytic reduction (SCR) articles, systems and methods provide for high NOx conversion while at the same time low N.sub.2O formation. The articles, systems and methods are suitable for instance for the treatment of exhaust gas of diesel engines. Certain articles have zoned coatings containing copper-containing molecular sieves disposed thereon, where for example a concentration of catalytic copper in an upstream zone is lower than the concentration of catalytic copper in a downstream zone.

Disclosed herein are methods and systems for the removal of volatile organic compounds, carbon monoxide and nitrogen oxides from off-gas, which systems comprise a source of ammonia, means for introducing ammonia into a catalytic article having an SCR functionality; a catalytic article having both an oxidation and an SCR functionality, the catalytic article comprising a catalyst substrate and a catalyst composition comprising at least one platinum group metal and/or at least one platinum group metal oxide, at least one oxide of titanium and at least one oxide of vanadium, wherein the washcoat is located in and/or on the walls of the catalyst substrate: means for measuring the amount of NO.sub.x and/or the ammonia slip between the outlet end of the catalytic article and the stack or at the stack, at least one carbon monoxide source, and means for introducing carbon monoxide into the catalytic article.

A reactor for reducing the concentration of NO.sub.x in a stream comprising: an inlet for the stream; an outlet for a stream containing a reduced concentration of NO.sub.x ; one or more catalyst beds comprising a ceramic or metallic foam with a NO.sub.x reduction catalyst; one or more flow paths from the inlet to the outlet that passes through at least one catalyst bed wherein the catalyst beds are closed at the top and bottom so that the flow path through the catalyst bed passes through the sides of the catalyst bed in a lateral flow is described.

A honeycomb body having a honeycomb structure and a peripheral skin, the honeycomb structure having walls defining a plurality of cells including peripheral cells disposed directly adjacent to the peripheral skin. One or more of the peripheral cells is at least partially defined by a first wall surface, a second wall surface, and a skin surface portion extending between the first wall surface and the second wall surface. A continuously-varying radius extends from a first tangent to the first wall surface along the skin surface portion and to a second tangent to the second wall surface. Other honeycomb bodies, structures, and extrusion dies for forming honeycomb structures are disclosed.

Disclosed herein is a system for the removal of volatile organic compounds, carbon monoxide and nitrogen oxides from off-gas even at high NO.sub.2 to NO.sub.x ratios, wherein the amount of NO.sub.2 within NO.sub.x is higher than or equal to 50 mol-%, comprising a source of ammonia, means for introducing ammonia into a catalytic article having an SCR functionality; a catalytic article having both an oxidation and an SCR functionality, the catalytic article comprising a catalyst substrate and a catalyst composition comprising at least one platinum group metal and/or at least one platinum group metal oxide, at least one oxide of titanium and at least one oxide of vanadium, wherein the washcoat is located in and/or on the walls of the catalyst substrate: means for measuring the amount of NO.sub.x and/or the ammonia slip between the outlet end of the catalytic article and the stack or at the stack, at least one carbon monoxide source, and means for introducing carbon monoxide into the catalytic article. Optionally, an SCR catalytic article can be placed upstream of downstream of the cata-lytic article having both an oxidation and an SCR functionality. Also disclosed is a method for the removal of volatile organic compounds, carbon monoxide and nitrogen oxides from off-gas introducing carbon monoxide in order to keep the amount of NOx and/or the ammonia slip between the outlet end of the catalytic article and the stack or at the stack at predetermined values. The method makes use of the system according to the invention. The system and the method can be used for the cleaning of flue gas.

A catalyst bed comprising a ceramic or metallic foam comprising one or more NO.sub.x reduction catalysts is described. A method for reducing the concentration of NO.sub.x in a dust containing gas stream comprising: a) passing a first gas stream containing NO.sub.x into a contacting zone; b) contacting the first gas stream with a ceramic or metallic foam catalyst bed having one or more flow paths through the catalyst bed wherein the ceramic or metallic foam comprises a NO.sub.x reduction catalyst to produce a second gas stream with a reduced NO.sub.x concentration; and c) passing the second gas stream out of the contacting zone wherein the first gas stream has a dust concentration of at least 5 mg/Nm.sup.3 and the pressure drop of the foam catalyst bed increases by 300% or less relative to the initial pressure drop of the foam catalyst bed due to dust accumulation, measured under the same conditions is also described.