| 摘要 |
PURPOSE:To obtain a catalyst of high heat resistance having sufficient activity at elevated temp. over a long period of time in performing catalytic reduction of NOX in the presence of NH3 by forming the carrier of catalysts of composite oxides contg. P as a constituting element. CONSTITUTION:This catalyst contains both components of A) >=1 kinds of 3- or 4-element composite oxides consisting of Ti, P, Si and/or Zr, and B) oxides of >=1 kinds of W, Ce, Sn. Here, the component A per se has activity for the NOX in waste gases, and also plays the role of a carrier. This is a solid acid and exhibits marked acidity not observed in respective independent oxides, and has high heat resistance coupled with high specific surface area. With the P in the component A, various effects can be observed; above all, it suppresses particularly the oxidation of NH3 to NOX and the crystallization of catalyst components. As a result, it maintains high activity for a long period of time. |
