Direct catalytic decomposition of NO with Cu–ZSM-5: A DFT–ONIOM study

ONIOM calculations for the direct catalytic decomposition mechanism of NO2 and NO by Cu–ZSM-5 were carried out. In two layer calculations, Density Functional Theory and Universal Force Field were employed for the high and low level models, respectively. ΔH° and ΔG° evaluations were performed in order to determine the thermodynamically more favored way for catalytic decomposition of NO2 and NO. The results show that a novel copper κ2 mononitrosyl species (Z–2Cu–κ2NO) is in equilibrium with the Z–2CuNO and Z–2CuON species. According to our results, the Z–2Cu–κ2NO species is the intermediary key of the direct catalytic decomposition mechanism of NO2 and NO by Cu–ZSM-5.

A DFT–ONIOM calculations were carried out to investigate the direct catalytic decomposition mechanism of NOx by Cu–ZSM-5. For the first time, the copper κ2 mononitrosyl species is reported.Figure optionsDownload high-quality image (87 K)Download as PowerPoint slideHighlights
► The use of ONIOM methodologies makes possible a combined quantum mechanism/molecular mechanism calculations in system with hundreds of atoms.
► The DFT calculations provide new insights in the direct DeNOx mechanisms by Cu–ZSM5 systems.
► The species [Cu–κ2NO]+ account for the liking species between the two-path mechanism.