Experimental and Theoretical Study of CO Oxidation on PdAu Catalysts with NO Pulse Effects

The effect of NO on CO oxidation was studied for Pt, Pd and PdAu catalysts. It was found that NO inhibits significantly the CO oxidation reactivity on both Pt and Pd catalysts. On PdAu catalyst, however, the presence of NO resulted in an enhancement of CO oxidation activity. In order to gain an atomistic understanding of this effect, density-function theory (DFT) calculations were performed on the adsorption and reaction properties of NO and CO on these metal surfaces. We have identified that the inhibition effects on Pt and Pd catalysts are due to stronger NO binding, and that the enhanced reactivity on PdAu is due to the reduced NO oxidation barrier on PdAu leading to NO2 formation.