Computational Evaluation of Potential Molecular Catalysts for Nitrous Oxide Decomposition

Area of Science:

• Computational Chemistry
• Catalysis
• Environmental Science

Background:

• Nitrous oxide (N2O) is a potent greenhouse gas (GHG) with limited applications and significant environmental impact.
• Effective mitigation strategies for N2O require efficient decomposition methods.
• While heterogeneous catalysts exist, there's a need for highly efficient, stable molecular catalysts and a deeper understanding of N2O splitting mechanisms.

Purpose of the Study:

• To computationally evaluate three molecular catalysts for nitrous oxide (N2O) splitting.
• To provide mechanistic insights into the N2O decomposition pathways.
• To identify promising homogeneous catalysts for N2O mitigation.

Main Methods:

• Density Functional Theory (DFT) calculations were employed to assess the structures and energetics of intermediates and transition states.
• A two-stage reaction pathway involving deoxygenation (DO) and dioxygen evolution (OER) was investigated.
• Three potential molecular catalysts were studied: one Cu(I)-based and two Ru(III)-based complexes.

Main Results:

• The Cu(I)-based catalyst facilitates N2O deoxygenation via bimetallic interaction, followed by favorable O2 dissociation.
• The Ru(III)-based catalyst (Cl(POR)Ru) shows facile N2 evolution and nearly thermoneutral O2 dissociation.
• The other Ru(III)-based catalyst (NTA)Ru exhibits exergonic N2O coordination and facile N2 dissociation, with moderately endergonic O2 evolution.

Conclusions:

• Cu(I)-based and Cl(POR)Ru derivatives are identified as the most promising candidates for efficient N2O decomposition.
• The computational evaluation provides valuable mechanistic insights into homogeneous N2O splitting.
• These findings can guide the development of more active and robust catalysts for N2O mitigation.