NOx removal catalyst, honeycomb structure type NOx removal catalyst, and NOx removal method using the same

摘要

A denitrification catalyst and a honeycomb structure type denitrification catalyst which are used for efficiently removing nitrogen oxides through reduction from exhaust gases discharged from, e.g. , boilers and internal combustion engines such as a gasoline engine and diesel engine; and a method of denitrification using either of these catalysts. The denitrification catalyst is for use in reducing nitrogen oxides contained in an exhaust gas with an ammonia source and comprises zeolite as the main ingredient, and is characterized in that not only iron element and cerium element but tin element and/or gallium element has been deposited on the zeolite. The honeycomb structure type denitrification catalyst comprises the denitrification catalyst and a honeycomb structure support whose surface has been covered therewith. The denitrification method is characterized by adding ammonia or urea as a reducing agent to an exhaust gas containing nitrogen oxides and bringing the mixture into contact with the denitrification catalyst or honeycomb structure type denitrification catalyst at a temperature in the range of 170-550°C.