| 摘要 |
PURPOSE:To easily produce a catalyst for purification of exhaust gas having enhanced NOx removing performance by supporting a transition metal and/or an alkaline earth metal on specified zeolite by ion exchange and heat-treating the zeolite. CONSTITUTION:A transition metal such as Cu or Mg and/or an alkaline earth metal is supported on zeolite having 5-1,000 ratio of Si to Al, e.g. ZSM-5 by ion exchange in an aq. soln. The zeolite is then heat-treated usually at about 500-800 deg.C for several hr in a flow of an inert gas such as Ar or N2 mixed with 0.05-5vol.% hydrogen or hydrocarbon such as methane or in a flow of air mixed with a prescribed amt. of water. Since the percentage of the catalytic metal acting as an active site is increased or the basicity of the resulting catalyst is increased, the catalyst accelerates the decomposition of NO molecules and increases the rate of removal of NO. |
