Unveiling Zeolite Confinement Effects on N₂O Decomposition Reaction over [Cu₂(μ-O)]²⁺ Active Sites

The development of design strategies to mitigate nitrous oxide (N2O) is essential due to its potentially harmful effects on the environment. Direct catalytic decomposition of N2O to nitrogen and oxygen could be an elegant solution, and copper-loaded zeolites represent powerful catalytic materials in this regard. Herein, we provide a theoretical understanding of the role of the confinement effect on the N2O decomposition reaction anchored by the active site mono(μ-oxo)dicopper species, [Cu2(μ-O)]2+, supported by zeolites of the type AEI, CHA, MFI, FAU, and MAZ. The proposed reaction involves N2O cleavage via a bent transition state and further desorption of O2. The quantum mechanics/molecular mechanics (QM/MM) calculations show that activation of N2O follows the order FAU ∼ MAZ > MFI > AEI ∼ CHA, indicating that large-pore zeolites exhibit higher activity compared to that of small-pore zeolites. The significant difference in the O2 desorption energies among various zeolites is demonstrated by the quantum theory of atoms in molecules (QTAIM) analysis. Furthermore, the bonding features of different dicopper-bound peroxo species obtained during the reaction are adequately compared with that of the [Cu2(μ-O)]2+ active core. The theoretical findings obtained herein offer significant insights into the structural features and catalytic abilities of various [Cu2(μ-O)]2+ centers, elucidating how variations in the zeolite topology and cavity structures influence the N2O decomposition reaction.