Catalysts for lean NOx reduction: structure-property relationship

Effective reduction of NOx to N2 using hydrocarbon in the presence of a high concentration of O2 can be accomplished using Al2O3-supported Co, Ag, or Au catalysts. However, the maximum NO conversion to N2 is higher on catalysts of lower metal loadings in the case of Co and Ag, which is due to the fact that the metal ions in these catalysts are more dispersed and more difficult to undergo redox than ions in catalysts of higher metal loadings. In the case of View the MathML source, the maximum NO conversion to N2 depends on the crystallite size of Au. The effect of the presence of NO on the hydrocabon oxidation reaction depends on the combustion activity of the catalysts: NO suppresses hydrocarbon combustion on more active combustion catalysts but facilitates it on less active ones.