| 摘要 |
PROBLEM TO BE SOLVED: To improve the CO and HC transformation ratio, keep the NOx treatment efficiency not lower than that of a conventional technique, and at the same time to suppress the production of SO3 gas and sulfates at the time of treating an exhaust gas by adding hydrocarbons to the exhaust gas in an excess oxygen atmosphere. SOLUTION: This catalyst is a monolith catalyst and produced by obtaining a platinum-carrying silica powder with a particle size of 17-35 nm by firing a silica powder carrying tetraammine platinum at 700 deg.C for 3 hours in atmospheric air, mixing a zeolite powder having hydrocarbon absorptive capability and a ceria-zirconia having oxygen absorbing and desorbing capability with the obtained powder, making a slurry of the powder mixture, applying the slurry to a honeycomb substrate made of cordierite, and firing the resultant honeycomb substrate at 350 deg.C. |
