| 摘要 |
<p>PURPOSE:To promote a rate of purification of NOX without lowering the rates of purification to HC and CO by a method wherein a mixture of plastinum and rhodium is sticked to a carrier in alumina and heated, a mixture of rhodium is attached and heated, and rhodium is diffused and moved to the outer surface side. CONSTITUTION:A mixture of platinum and rhodium is sticked on the surface of a carrier in alumina by means of application, etc., and heated at a temperature of 1100 deg.C or more in atmospheric air. Rhodium is diffused and moved on the outer surface without being oxidized by the heating, and rhodium is under a rich condition on the outer surface more than the carrier side. The purifying effect of NOX can be promoted without lowering the purifying effect of CO and HC by using the three elements catalyst. Thus, the air-fuel ratio of gas used can be reduced, and fuel cost can be decreased.</p> |
