Catalytic Reduction of Nitrous Oxide by the Low-Symmetry Pt Cluster.

The search for a catalyst for the reduction of nitrous oxide (NO) is now imperative, as this molecule is a very dangerous pollutant. We found that the low-symmetry Pt cluster presents multiple reaction pathways for NO rupture, which are regioselective. This result was revealed by means of density functional theory calculations within the zero-order-regular approximation, ZORA, explicitly including relativistic effects. It is further proved that Pt is a competitive NO catalyst compared to sub-nanometric rhodium clusters, obtaining similar reaction barriers. The hot adsorption site, a tip atom of Pt, and the rotation of the NO molecule over the metallic cluster promote the formation of a frustrated bridge activated transition state, Pt-NO. This transition structure yields to spontaneous dissociation of NO without bridge formation. Along this catalytic process, rearrangements within the metal cluster take place, preserving its stability. Moreover, in addition to being important attributes of the Pt particle in the NO reduction, fluxionality and multiple reaction pathways may also prevent poisoning effects. Overall, this differs from reported results for more symmetric metal particles also used as catalysts.