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 catalytic material for treating an exhaust gas produced by a natural gas engine, which catalytic material comprises a molecular sieve and a platinum group metal (PGM) supported on the molecular sieve, wherein the molecular sieve has a framework comprising silicon, oxygen and optionally germanium, and has a content of heteroatom T-atoms is about 0.20 mol %.

Method for the preparation of a catalyst comprising vanadium pentoxide supported on a metal oxide catalyst carrier comprising the steps of a) providing particles of crystalline vanadium pentoxide and particles of a metal oxide catalyst carrier; b) solid state mixing the particles and dispersing the vanadium pentoxide particles on surface of the metal oxide carrier particles; and c) anchoring the dispersed vanadium pentoxide particles on surface of the metal oxide carrier particles by calcination at a temperature above 500 C., characterized in that sintering of the vanadium pentoxide particles is suppressed by addition of an anti-sintering metal oxide component, such as tungsten trioxide, during the anchoring in step c).

A method for the preparation of a catalyzed monolithic body or a catalyzed particular filter. The method includes the step of suctioning a sol-solution containing catalytically active material and metal oxide catalyst carriers or precursors thereof into pores of a monolithic substrate, solely by capillary forces and without the application of vacuum or pressure.

A reducing agent injection device includes a honeycomb structure and a urea spraying device spraying a urea water solution in mist form. In addition, the reducing agent injection device includes a carrier gas inlet that introduces carrier gas f between the urea spraying device and the honeycomb structure. The exhaust gas treatment method of the present invention supplies the urea water solution from the urea spraying device into the cells from the first end face of the honeycomb structure body to generate the ammonia, while introducing the carrier gas f from the carrier gas inlet, and injecting the ammonia to the outside to treat exhaust gas containing NO.sub.X.

A combustion system operated at low cost is provided. A combustion system 1 includes a combustion device 10 that burns fuel, an exhaust line L1 through which exhaust gas flows, the exhaust gas being generated through combustion of the fuel in the combustion device 10, a dust collector 50 that is disposed in the exhaust line L1 and that collects dust in the exhaust gas, and a denitration device 90 that is disposed in the exhaust line L1 and that removes nitrogen oxide from the exhaust gas using a denitration catalyst. The denitration device 90 is disposed downstream from the dust collector 50 in the exhaust line L1. The denitration catalyst contains 43 wt % or more of vanadium pentoxide and has a BET specific surface area of 30 m.sup.2/g or more.

A method for regenerating a deactivated denitration catalyst includes steps of preparing a washing fluid including a water-contained liquid and entrained carbon dioxide bubbles, and subjecting the deactivated denitration catalyst to a treatment with the washing fluid. An apparatus for regenerating the deactivated denitration catalyst is also provided.

Described are SCR catalyst systems comprising a first SCR catalyst composition and a second SCR catalyst composition arranged in the system, the first SCR catalyst composition promoting higher N.sub.2 formation and lower N.sub.2O formation than the second SCR catalyst composition, and the second SCR catalyst composition having a different composition than the first SCR catalyst composition, the second SCR catalyst composition promoting lower N.sub.2 formation and higher N.sub.2O formation than the first SCR catalyst composition. The SCR catalyst systems are useful in methods and systems to catalyze the reduction of nitrogen oxides in the presence of a reductant.

Disclosed are an extruded honeycomb catalyst, a process for preparing the catalyst, a method for reducing NOx in the exhaust gas from an internal combustion engine by using the catalyst, and a method for treatment of the emission gas generated from power plant comprising exposing the emission gas to the catalyst.

An exhaust gas treatment system for an internal combustion engine includes an exhaust gas pathway that receives exhaust gas from the engine, a temperature sensor configured to generate a temperature signal associated with a temperature of the exhaust gas at a position along the exhaust gas pathway, and a reductant source. The system also includes first and second injectors in fluid communication with the reductant source. The first and second injectors are configured to inject reductant into the exhaust gas pathway at first and second rates. The system also includes a first treatment element positioned downstream of the first injector and within the exhaust gas pathway, and a controller in communication with the temperature sensor. The controller is configured to receive the temperature signal from the temperature sensor and adjust at least one of the first rate or the second rate based at least in part on the temperature signal.