The Frist Principle Study Of The Interaction Of N₂O With Ir(100)

Nitric oxide (N2O) is one of the main greenhouse gases, and it is a by-product of NOx catalytic decomposition..The interaction between N2O and transition metals has attracted more and more attention from the surface scientists because of their importance in both scientific researches and applications. The experimental studies reveal that the interaction of N2O with Ir (111) and (110) surface is active, while the interaction of N2O with Ir(100) is inert. Up to now there is no theoretical investigation for the interaction of N2O with Ir surface.We have performed the first principle calculation based on density-function theory for N2O on Ir(100). The essential results and conclusions we have got from this work could be outlined as follows. All possible configurations of N2O adsorption on the Ir(100) surface have been identified.for the case that an atom of N2O interacting with the surface. The most stable situation via the N-terminal is on an atop site of Ir(100) with the linear N2O molecule situated nearly perpendicular to the surface. Other stable adsorption modes via the two N atoms or the terminal N and O atoms have been identified. It is shown that the two adsorption modes activate the molecule by weakening N-O bond or N-N bond, which may lead to its dissociation and subsequent formation N2 or NO. In the Ir (100) surface, there is a situation that N2O decomposition may occur, while N2O don't need to be activated. When we put N2O along some direction, it can be dissociated into N2 and O thorough relaxation optimization. The energy released by the decomposition process is around the 2eV. Comparing DOS of gas N2O with that of N2O on Ir(100) with c (2x2) structure, we found that N2O interacts with the substrate through 7σorbital for N2O adsorption on Ir (100) via Nt, while for other two stable modes of N2O on Ir (100) via two atoms, the 2πand 3πorbitals are mixed with substrate orbitals and the back donation 3πorbital leads to N2O activated and its bonds enlarged.In summary, our study reveals that the interaction of N2O with Ir (111) and (110) surface is active, which is similar with N2O on (100) surface of 4d transition metal Rh.