| 摘要 |
PURPOSE:To simultaneously remove hydrocarbon, CO and NOx in exhaust gas by using a catalyst obtd. by supporting Pt, Pd or Rh and Cu and/or Co on crystalline gallium silicate having a specified compsn. CONSTITUTION:Crystalline gallium silicate represented by formula I (where M is an Na or K ion and (n)<27) is synthesized by hydrothermally synthesizing water glass as a prescribed silicate and Ga ions. Pt, Pd or Rh and Cu and/or Co are then supported on the gallium silicate to obtain a catalyst. Since this metal supported gallium silicate catalyst accelerates the reaction of hydrocarbon with NOx in exhaust gas in preference to the reaction of the hydrocarbon with oxygen, the hydrocarbon and NOx in the exhaust gas can be removed. The hydrocarbon present in the exhaust gas to be purified may be hydrocarbon remaining in ordinary exhaust gas. |
