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.

Ceramic candle filter and use of the filter in the removal of particulate matter in form of soot, ash, metals and metal compounds, together with hydrocarbons and nitrogen oxides being present in process off-gas or engine exhaust gas, the filter comprises a combined SCR and oxidation catalyst arranged at least on the dispersion side and/or within wall of the filter, the combined SCR and oxidation catalyst comprises palladium, a vanadium oxide and titania.

Ceramic candle filter and use of the filter in the removal of particulate matter in form of soot, ash, metals and met-al compounds, together with hydrocarbons and nitrogen oxides being present in process off-gas or engine exhaust gas, the filter includes a combined SCR and oxidation catalyst being arranged on the dispersion side and within wall of the filter; and a palladium including catalyst arranged on the permeation side and within wall of the filter facing the permeation side.

Provided is a catalytic converter, having a first casing, a first honeycomb carrier disposed in the first casing, multiple second casings connected to the first casing, and multiple second honeycomb carriers each respectively disposed in the second casings. The first honeycomb carrier has multiple first metal sheets and a first catalyst layer formed on the first metal sheets. The first metal sheets are disposed in the first casing to form multiple first channels. Each of the second honeycomb carriers has a similar structure with that of the first honeycomb carrier. The materials of the first and the second catalyst layers include platinum, palladium, and rhodium. The exhaust gas is subjected to redox reaction by the first and the second catalyst layers and burned at high temperature, and thus the emission of the harmful components from the diesel engine is reduced.

Provided is a catalytic converter, having a first casing, a first honeycomb carrier disposed in the first casing, multiple second casings connected to the first casing, and multiple second honeycomb carriers each respectively disposed in the second casings. The first honeycomb carrier has multiple first metal sheets and a first catalyst layer formed on the first metal sheets. The first metal sheets are disposed in the first casing to form multiple first channels. Each of the second honeycomb carriers has a similar structure with that of the first honeycomb carrier. The materials of the first and the second catalyst layers include platinum, palladium, and rhodium. The exhaust gas is subjected to redox reaction by the first and the second catalyst layers and burned at high temperature, and thus the emission of the harmful components from the diesel engine is reduced.

An exhaust gas after-treatment system for an internal combustion engine, with a particle filter arranged downstream of an internal combustion engine for filtering soot out of the exhaust gas, and with an oxidation catalytic converter arranged upstream of the particle filter and downstream of the internal combustion engine for the oxidation of SO.sub.2 into SO.sub.3. The SO.sub.3 and/or precipitated H2SO.sub.4 serves for the oxidation of soot in the particle filter and thus for the regeneration of the particle filter.

A methane purification apparatus includes a flow path through which a gas containing methane flows, an ozone supply unit that supplies ozone to the gas, a catalyst structure that is provided downstream of the ozone supply unit in the flow path and purifies the methane by causing the ozone to react with the methane, and a heater that is in contact with the catalyst structure in the flow path and heats the catalyst structure.