| 摘要 |
PROBLEM TO BE SOLVED: To provide a practical, highly active decomposition catalyst capable of removing NOx, especially, NO contained in exhaust gases originated from all combustion apparatus by directly decomposing them at a high temp. without reducing agents, and to provide the practical method for removing nitrogen oxides using the catalyst for treating the exhaust gas containing oxygen and steam. SOLUTION: The decomposition catalyst containing, as a catalytically active component, at least one metal complex oxide of the composition formula AB1-x Ex/2 Px/2 O3+-z , (A is an alkaline earth metal; B is an metal of the titanium group elements; E is a metal selected from vanadium group elements, P is each one metal selected from the copper group or platinum group elements), preferably, whose crystalline structure is a perovskite-type, is used for removing nitrogen oxides. As this catalyst has a high resistance against the poisoning caused by steam, the nitrogen oxides in the exhaust gas containing steam can be removed by directly bringing the exhaust gas into contact with the catalyst at 600-1,000 deg.C, in the presence of or in the absence of oxygen without removing moisture from and drying the gas and without adding reducing agents. |
