Dinitrosyl formation as an intermediate stage of the reduction of NO in the presence of MoO_3

TL;DR

This study uses first-principles calculations to explore how NO reduction on MoO3 involves forming dinitrosyl as a key intermediate, revealing energetic favorability and the role of the oxide in the process.

Contribution

It provides the first detailed computational analysis of dinitrosyl formation during NO reduction on MoO3, highlighting the energetic and structural aspects of this intermediate.

Findings

Replacing oxygen with NO is energetically favorable.

Formation of (NO)$_2$ lowers the system energy.

Dinitrosyl exhibits metal-oxide mediated coupling.

Abstract

We present first-principles calculations in the framework of density-functional theory and the pseudopotential approach, aiming to model the intermediate stages of the reduction of NO in the presence of MoO$_3$(010). In particular, we study the formation of dinitrosyl, which proves to be an important intermediate stage in the catalytic reduction. We find that the replacement of an oxygen of MoO$_3$ by NO is energetically favorable, and that the system lowers further its energy by the formation of (NO)$_2$. Moreover, the geometry and charge distribution for the adsorbed dinitrosyl indicates a metal-oxide mediated coupling between the two nitrogen and the two oxygen atoms. We discuss the mechanisms for the dinitrosyl formation and the role of the oxide in the reaction.