| 摘要 |
PURPOSE:To provide a catalyst for purification of exhaust gas having excellent durability at high temp. and a high rate of removal of NOx at high temp. CONSTITUTION:This catalyst consists of heat resistant modified ZSM-5 zeolite and Mn carried on the zeolite by ion exchange. In the heat resistant modified ZSM-5 zeolite, the X-ray reflection intensity of at least one crystal face (f) among plural crystal faces CF1 whose Miller indices (h), (k), (l) are <=2 each in a 1st group of crystal faces having >=4.0Angstrom interplanar spacing is increased by >=4% as compared with the X-ray reflection intensity of the same crystal face (f) of the unmodified ZSM-5 zeolite. This catalyst is proof against heat at 900 deg.C and has 26% rate of removal of NOx at 500 deg.C. |
