| abstract |
A process is provided for the production of a catalyst useful for removing nitrogen oxides out of exhaust gases from internal combustion engines operated under lean burn conditions. The catalyst is produced by supporting at least one catalytic metal, such as platinum, iridium, rhodium, other transition metals and alkaline earth metals, as the active component on a support, such as a zeolite, by either wash-coating a solution of the catalytic metal components onto the support; evaporating off solvent from a mixture of solvent, catalyst material and support, or rapidly drying droplets of support and catalyst material containing slurry with a hot gas. The supported catalyst is activated by heating to a temperature of 150 to 300 DEG C. for a period of time sufficient to desorb catalytic material components, such as water, chlorine and ammonia, out of the pores of the catalyst that adversely affect the activity and heat resistance of the catalyst. |