| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a substantially excellent exhaust gas purification catalyst and exhaust gas purification method capable of removing nitrogen oxides in exhaust gas, and preventing the catalyst from decreasing a capacity due to the deposition of carbon materials on the catalyst even with high concentration of the nitrogen oxides in the exhaust gas. <P>SOLUTION: In the exhaust gas purification method, an upstream side in a flow direction of the exhaust gas is disposed with a first catalyst wherein silver and/or molybdenum are/is supported on a beta-zeolite, and its downstream side is disposed with a second catalyst comprising a proton type beta-zeolite. The first and second catalysts are brought into contact with an exhaust gas containing excess oxygen in the presence of methanol and/or dimethyl ether, thereby reducing and removing nitrogen oxides in the exhaust gas. The ratio of the first to second catalyst is preferably within the volume ratio of 1:9-5:5. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
