NITRIC-OXIDE REDUCTION OVER CARBON-SUPPORTED PALLADIUM CATALYSTS

The reduction of NO by CO is performed over palladium supported on act ivated carbons and on a graphite of lower surface area. The presence o f very low amounts of Pd gives active and stable catalysts towards the NO-CO reaction and the contribution of the surface carbon atoms to th e process is negligible, the presence of CO lowering the consumption o f the carbon support by NO. In the absence of any other reductant in t he gas phase, NO is reduced by reaction with the carbon atoms. In the presence of an excess of O-2 (net-oxidizing NO-CO-O-2 mixtures), the c onsumption of the carbon supports by O-2 is important. The reactions o f NO with the C atoms are also inhibited, NO reacting with CO but O-2 reacts with both reductants, CO and C.