COMPUTER-AIDED-DESIGN OF ACTIVE CATALYSTS FOR THE REMOVAL OF NITRIC-OXIDE

We report here our computational studies on metal-exchanged ZSM-5 catalysts using molecular dynamics and computer graphics techniques. The structure and the dynamic behavior of copper, gallium and cerium cations in cation-exchanged ZSM-5 framework were studied. Various oxidation states of these metals were simulated and their relevance in the catalytic removal of nitric oxide is discussed. The high Si/Al ratio in ZSM-5 explains the existence of an equilibrium between the different oxidation states of exchanged copper cation, which favors NO reduction. The higher mobility of the oxygen atom attached to gallium and cerium, and the low coordination of these cations are also reasons for their catalytic activity.